Revised September 13, 2006
Glossary of Avian Terms

For Use in Avian Conservation Biology

Provided by the USGS

Brief definitions of basic concepts and terms in addition to notes on important figures in American ornithology.
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J, K, L
Q, R, S
U, V, W
X, Y, Z

Adaptation - An organism's ability to exist in a particular environment comes from adjustments that they have made as a species. Owls have adapted to hunting at night by having large eyes (Barn Owl); many species use camouflage that helps them hide in their environment (American Bittern); a specially adapted beak that gives a species an advantage to feed on hard to reach organisms (Long-billed Curlew). All these special traits are considered adaptations. From A Dictionary of Birds: the production of fitness for a particular function, the term being also applied to a character (structure, behaviour, etc.) specially providing such fitness. 'Adaptive radiation' denotes divergence in the characters of related forms that enables them to exploit different kinds of opportunity. 'Convergence' denotes the adaptation of unrelated forms to similar functions, often giving rise to superficial resemblance."

From The Birdwatcher's Companion : "Adjustment, by an organism, sometimes in a striking and/or highly specialized way, to a particular way of life. A widely applicable term that may relate to structure, function, and/or behavior. Cryptic coloration, night vision, and canopy feeding, for example, are all adaptive characteristics of certain groups of birds.


Albinism - An abnormal lack of pigment. Albino Red-tailed Hawk


Allopatric - Mutually exclusive geographically as contrasted with sympatric. From The Birdwatcher's Companion : Separated geographically; usually refers to closely related species or subspecies whose breeding ranges, although adjacent, do not overlap. In this situation the possibility of interbreeding cannot be tested because the two forms do not normally meet.


Alternate plumage - The spring plumage which is also referred to as the breeding plumage; the basic plumage is the plumage the bird has during the winter or the non-breeding time.


Altricial - Birds that are born without feathers, the ability to see, or the ability to feed themselves are called altricial. There are different levels of altricial young. Some are born with their eyes closed and no down, some have their eyes open and substantial down on them. But all altricial young need to be fed by their parents in contrast with precocial young which feed themselves within hours of being born. See Young birds.


American Ornithological Union - (From Wikipedia) The American Ornithologists' Union (AOU) is the oldest and largest ornithological organization in the Western Hemisphere. Unlike the National Audubon Society, its members are primarily professional ornithologists rather than amateur birdwatchers. It was founded in September 1883 by Elliott Coues, Joel Asaph Allen and William Brewster. Its quarterly journal, The Auk, has been published since January, 1884. Other significant publications include the AOU Checklist of North American Birds, which is the standard reference work for the field, and a monograph series, Ornithological Monographs.


Amphipods - From Wikipidia: "Amphipods range in size from 1 to 340 millimetres (0.039 to 13 in) and are mostly scavengers. There are more than 9,500 amphipod species so far described. They are mostly marine animals, but are found in almost all aquatic environments. Marine amphipods may be pelagic (living in the water column) or benthic (living on the ocean bottom). Pelagic amphipods are eaten by seabirds, fish and marine mammals. Terrestrial amphipods such as sand fleas can often be seen amongst grains of sand and pebbles or on beaches."


Animals - Formerly the living world was divided into two kingdoms: animals and plants. All mammals are animals, but not all animals are mammals. Birds are animals. All birds are animals but not all animals are birds. All insects are animals but not all animals are insects. One of the most common mistakes made is to refer to "animals and birds" when they mean to say "mammals and birds."


Anting - An example of care behavior. From A New Dictionary of Birds: "This consists of special movements, apparently confined to passerines, whereby the defence and other body fluids of ants (Hymenoptera: Formicidae) are applied to the bird's feathers. The chief organic liquid involved is the formic acid produced by the worker (and queen) caste ants of species of the acid-ejecting Formicinae. ... The annointing of the feathers with ant fluids is effected either directly by the bird applying the ant to its plumage with its bill (active anting), or indirectly by its permitting the ants to swarm on it its plumage, ejecting formic acid (so-called passive anting)." Picture of American Robin anting.


Anthropomorphizing - Interpreting the behavior of non-human animals in terms of our understanding of human animals. There are some needs such as the need to eat, sleep, drink water, that are very similar between humans and non-human animals. In other cases the practice of interpreting animal behavior in human terms is not always warranted.


Arthropods - Phylum of segmented animals that have hard outer skeletons. Phylum includes insects, arachnids, and crustaceans. There are over 1 million species in this phylum. This is the largest phylum of invertebrates.


Audubon, John James - (1785 - 1851) Early American ornithologists and painter. He was one of the first to study the birds found in America. Some of his writing can be viewed in the natural history accounts of these species: Red-throated Loon, Great Egret, Snowy Egret, Black-crowned Night Heron, Roseate Spoonbill, White Ibis, Ring-necked Duck, Lesser Scaup, Mottled Duck, Mississippi Kite, Chipping Sparrow, Magnificent Frigatebird, Whooping Crane, Pileated Woodpecker, Florida Scrub Jay, Cliff Swallow, Western Tanager,


Audubon Society - Founded in 1896; the primary goal of the Audubon Society is to promote conservation of natural resources and encourage awareness of nature.


Avian Dispersal - Movement of individuals from an area of high intensity to areas of low intensity. Often this term refers to movement of recently fledged birds to an area other than where they were born.


Avian Intelligence - The intelligence of birds is difficult to define. To many scientists, when birds participate in problem solving, or demonstrate memory, or cognitive mapping, they demonstrate signs of intelligence. Some people argue that it is not intelligence, but rather advanced stimulus response. Some birds, such as members of the Corvidae family, demonstrate advanced memory and advanced problem solving. The natural history notes from Bent for the Common Grackle and Western Gull demonstrates what many would consider to be examples of avian intelligence. See Learning.


Aviary - A structure used to house birds. Many zoos have large aviaries that visitors may walk within and view the birds. In Birdcentral, the Rufous Hummingbird, Common Moorhen, Greater Flamingo, Yellow Grosbeak, Brewer's Sparrow, Hooded Oriole, were photographed in aviaries.


Bailey, Florence Merriam - (1863 - 1948) American ornithologist, who wrote the Handbook of Birds of the Western United States in 1902. Sister of C. H. Merriam. First female member of the AOU. Some of her writing can be viewed in the natural history accounts of these species: Western Kingbird Scissor-tailed Flycatcher, White-tailed Ptarmigan, Scaled Quail, Bridled Titmouse, Cactus Wren, Curve-billed Thrasher, Phainapepla, Green-tailed Towhee,


Baird, Spencer - (1823 - 1887) Early American Ornithologist. The Baird's Sandpiper and Baird's Sparrow were named after him.

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Banding - The science of studying birds by gathering data on their movements and age. This is done by putting a very light aluminum band around one of their legs. The band has a number which is recorded in a book with all appropriate data. When the bird dies or is recaptured the band is recovered and scientists retrieve data about how far the bird has traveled and how long it has lived, in addition to other data. This White-crowned Sparrow has a band on its leg. For a look at some of the work of a banding station check out this page from the Ft. Steven's banding station in the state of Washington.


Basic plumage - The plumage a bird has during its non-breeding time which is most of the year. The alternate plumage is the plumage during the breeding time.


Bathing - A type of care behavior for birds. From The Birdwatcher's Companion "Almost all birds wet their feathers in some manner on a regular basis as part of their ritual of plumage maintenance. Some desert birds seldom or never take water baths, and gallinaceous birds substitute dust baths at least in most instances. Most authorities seem to agree that birds bathe not as a direct cleaning process as humans do, but more as a preparation for preening and oiling the feathers. As is true of most other forms of bird behavior, bathing is not done haphazardly but rather in a sequence of characteristic gestures which vary consistently among different types of birds. Observations of both captive and wild young birds suggest that the urge to bathe is innate, though some of the particular gestures of the wetting and drying process may be learned or at least triggered by watching older individuals."


Beak - The jaws of the bird; the tool that the bird uses to eat with. The type of beak that the bird has determines the type of food that is easiest to eat. The Snail Kite has a beak that is especially adapted to eat large snails. The Long-billed Curlew has a beak that is specially adapted to probe deep in the sand, while the Black Turnstone has a beak that is good for turning over small stones. The Black Turnstone does not compete with the Curlew for food because it can't obtain the type of food that the Curlew eats. The Broad-billed Hummingbird cannot eat the seeds that the Black-headed Grosbeak eats. Different species that seem to have the same type of beak really are more different than we think and this helps them to not compete for the same type of food. (See Gause's Rule of Non-Competition)


Behavior - How an animal responds to the outside world. The behavior of a Black-necked Stilt is much different from the behavior of the Cooper's Hawk. Behavior is one of the themes included in the education section.


Bell, John - (1812 - 1889) American ornithologist and associate of John James Audubon. Bell's Vireo and Sage Sparrow (Amphispiza belli) were named after him. From The Birdwatcher's Companion "A well-known collector and taxidemist from New York State who accompanied his friend John James Audubon on the latter's expedition up the Missour River in 1843. He was also known and liked by eminent ornithologists of the next generation, e.g., Baird, Ridgway, Cassin, and Le Conte. Aududon named the vireo for him, Ridgeway the sparrow, and an ornithologist name Giraud added a Mexican warbler species now known as the Golden-browed Warbler (Basileuteris belli).


Bendire, Charles E. - (1836 - 1897) A Major in the US Army who started the Life Histories of North American Birds which became the 26-volume series finished by A. C. Bent. The Bendire's Thrasher was named after Bendire. Some of his writing can be viewed in the natural history accounts of these species: Yellow-billed Cuckoo, Lewis Woodpecker, Blue Jay, Eastern Wood Pewee, Vermillion Flycatcher, Florida Scrub Jay

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Bent, Arthur C. - (1866 - 1954) Beginning in 1919 Arthur Cleveland Bent gathered information on the status of birds in the 48 states. This material, which when finished, consisted of 26 volumes, was published originally by the US Government and later republished by Dover Books as the Life Histories of North American Birds. A. C. Bent died in 1954 before the completion of the project which was finished in the 1960s by Oliver Austin Jr.. The Life Histories of North American Birds is one of the best sources of information on distribution, behavior, and food for each species. It also provides an historical context for understanding our views on natural resources and our efforts to maintain those resources.


Bergmann's Rule - (From The Birdwatcher's Companion ) "The observation (formulated by a nineteenth-century German Zoologist) that overall body size tends to be greater in representatives of bird and mammal species living permanently in cooler climates than in those living in warmer climates. Put simply, American Kestrels in Maine (Falco sparverius sparverius) are larger on the average than those in Florida (F. s paulus). The ecological principle followed is that large bodies retain heat more efficiently than small ones, and that there is therefore an adaptive size increase in populations constantly subjected to lower temperatures."


Biology - The study of living organisms. This includes, but is not restricted to, zoology and botany and other studies.


Biome - Plant communities such as chaparral, tundra, coniferous forest, deciduous forest, grassland, southwestern (U.S.) pine-oak woodland, pinyon-juniper woodland, chaparral, and desert. There are many different types of plant communities. They can be broken into eight large categories.

  1. Grasslands which includes prairie grassland, tallgrass prairie, mixed grass prairie, short grass prairie
  2. Forest which can be broken down into 18 types of forest: boreal forest, riparian woodland, western forest, northwestern coastal forest, open oak woodlands, pinyon juniper woodlands, eastern forest, northern hardwood forest mixed deciduous forest, coastal plain pine oak forest, savannah, subtropical forest, Florida subtropical hammock, mangrove swamps, and South Texas mesquite
  3. Shrublands which includes chaparral and shrubland
  4. The desert which includes Great Basin Desert, Mojave Desert, Sonoran Desert, Chihuahan desert
  5. Tundra which can include Arctic tundra, low-arctic tundra, high arctic tundra, and alpine tundra
  6. Wetlands and Aquatic habitat which includes rivers and streams, freshwater marsh, saltwater marsh, and lakes and ponds
  7. Ocean habitat which includes coastal environment, and coastal waters and open ocean
  8. Urban areas which includes farms, suburbia and cities.

One basic categorization of biomes lists five types:

  • Aquatic,
  • Deserts,
  • Forests,
  • Grasslands,
  • Tundra.

Another way to categorize the biomes:

  • Tundra and Arctic Deserts,
  • Temperate Needleleaf Forests or Woodlands,
  • Temperate Broadleaf Forests or Woodlands,
  • Temperate Grasslands,
  • Cold Winter Deserts and Semi-Deserts,
  • Evergreen Forests
  • Scrub or Woodland,
  • Tropical Grasslands and Savanna,
  • Warm Deserts and Semi-Deserts,
  • Tropical Dry or Deciduous Forests or Woodlands,
  • Tropical Humid Forests,
  • Mixed Mountain and Highland Systems,
  • Mixed Island Systems.

Another system includes 11 biomes. See also Life Zones which is a system developed by C. H. Merriam.

Bird lice - (From Encyclopedia Britannica) "any chewing louse (Mallophaga) living on birds. Probably all bird species have chewing lice. Bird lice feed on feathers, skin surface, and sometimes blood but normally are not harmful."


Bird-of-the-Year - An expression used to describe an individual bird that was born in the current year. The Heerman's Gull page shows a bird of the year.


Birdwatching - The art and science of observing birds. It is done by amateurs and professionals alike. In fact there are many people who are birdwatchers who don't even know that they are birdwatchers. Beyond Birding is a good source that looks at the possibilities of bird-watching.


Breeding - The process of raising a family of birds. It requires courtship, nesting, feeding, and dispersal. Many species migrate to their breeding grounds.


Brewer, Thomas - (1814 - 1880) - American ornithologist. The Brewer's Sparrow and Brewer's Blackbird were named after him.


Brood - The young hatched from a clutch of eggs; a species of bird may have two or even three broods in a single breeding season.


Brood-parasitism - When one species uses a different species to raise their young, quite often to the damage of the parenting species. This is generally seen in the US when the Brown-headed Cowbird lays its eggs in the nests of many species of songbirds, especially warblers. The warblers end up raising the cowbird instead of their own young. Young Brown Headed Cowbird being fed by Oregon Junco.


Brooks, Maj. Alan - (1869-1946) Canadian naturalist and artist. Some of his writing can be viewed in the natural history accounts of these species: Bufflehead,


Burroughs, John - (1837 - 1921) - A nineteenth century writer and naturalist who, along with John Muir, helped to convince President Theodore Roosevelt to protect Yosemite by making it a National Park. Burroughs wrote a series of 23 books which studied primarily plants and animals of the east. Some of his writing can be viewed in the natural history accounts of these species: Ruby-crowned Kinglet, Eastern Bluebird, Pygmy Owl.

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Camouflage - When the plumage of an animal resembles the habitat where it lives and makes it difficult for other animals to find it. Some birds are particularly good at camouflage such as the American Bittern.


Care behavior - How a bird maintains its body. Basic functions that most birds utilize to care for their feathers such as bathing, drying, head scratching, anting, preening, sunning, and dusting.


Carrion - Dead animals. With the exception of vultures, crows, jays, gulls and a few others, most birds will not eat dead animals.


Carnivorous - Animals whose diet consists primarily of other animals.


Cassin, John - (1813 - 1869) American ornithologist. Cassin's Finch, Cassin's Vireo, Cassin's Auklet, Cassin's Sparrow, and Cassin's Kingbird, are named after him. Curator of birds at the Philadelphia Academy of Natural Sciences. He named the Brewer's Sparrow, and the Rufous-crowned Sparrow.


Census - Determining the numbers of birds within a particular area (see Christmas Count).


Chaparral - A dry shrub land found in the west; manzanita, chamisal and mahogany are typical plants. Wrentit is a good typical bird of the chaparral.


Chapman, Frank - (1864 - 1945) Curator of birds for 54 years at the American Museum of Natural History. Author of Birds of Eastern North America along with other volumes. Responsible for initiating the Christmas Count. Some of his writing can be viewed in the natural history accounts of these species: White Pelican, White-faced Ibis, Carolina Wren, Yellow Warbler, Hooded Warbler,


Christmas Count - During the last two weeks of the year, since the beginning of the twentieth century, thousands of birdwatchers census the birds found within their neighborhoods. Each location throughout the United States picks a single day to count the birds in a circle with a fifteen mile diameter.


Class - In the phylum vertebrates, there are five classes: fish, amphibians, reptiles, birds, and mammals. (Kingdom, Phylum, Class, Order, Family, Genus, Species)


Classification - The process of organizing the species. In the animal world the classification system uses Kingdom, Phylum, Class, Order, Family, Genus, Species. In the study of birds, the Kingdom = Animal Kingdom, Phylum = Vertebrates (animals with backbones), Class = Birds. In the study of North American birds we are currently (2006) recognizing 19 Orders and 67 families of birds. Classification is one aspect of zoology that is changing as we learn more about DNA and we use DNA/DNA comparison to re-evaluate which species is related to which. Classification expresses how we imagine nature is structured. (Kingdom, Phylum, Class, Order, Family, Species)


Cline - From A New Dictionary of Birds: "Term introduced by J.S. Huxley (1939) for a population aggregate (within a species) showing gradation in its characters from one end of its range to the other. A cline has itself no status in nomenclature. It may include forms to which subspecific names have been attached, although where the gradation is continuous (as happens in the absence of barriers) the validty of such subspecies becomes questionable. Nevertheless, the forms at the extremities of a cline may show striking differences when directly compared with each other, and this may be true also of intermediate forms taken from points sufficiently far apart in the clinal range. in such cases the use of subspecific names may have a practical convenience in providing taxonomic points of reference."


Clutch Size - The number of eggs within a nest.

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Color - The color we see when we view a bird. This can be more complicated than we imagine. The color of everything that we see is the result of the light waves that are reflected back to us. If we see a white bird such as the Gt. Egret , then all the light waves are being reflected back to us. When we see colors other than white there are two basic causes: structural colors and pigmental colors.

The color of a bird is the result of pigmentation and structural colors. Most of the colors that we see on a bird are the result of pigments. Structural colors, blue, black, and green, are either the result of interference (iridescence) or micro-structures of the feathers themselves. Iridescent colors are the result of lightwaves that interfere with each other. When we see the brilliant color of the Rufous Hummingbird that is the result of iridescence. Also when we see a Common Raven in the right light we see iridescence in its feathers.

As field ornithologists we have to realize that the color we see on a bird is quite often the result of the time of day that we see the bird. In the late afternoon colors can become a lot warmer. Take a look at the Marbled Godwit page and compare the pictures in the top right corner and the bottom left corner. It is the same species but it has been photographed at different times of the day producing different colors. The pictures on the bottom left were photographed in late afternoon and produce a warmer color.

Commensalism - (From Wikipedia) In ecology, commensalism is a class of relationships between two organisms where one organism benefits but the other is neutral (there is no harm or benefit). There are three other types of association: mutualism (where both organisms benefit), competition (where both organisms are harmed) and parasitism (one organism benefits and the other one is harmed).


Community - Refers to organisms living within a defined habitat. Organisms within a freshwater marsh are related in many ways, one of which is being part of a food web. Within many communities different bird species will feed together and benefit from the cooperation. Community ecology is a branch of science that studies the patterns of community members.


Comstock, Anna Botsford -  (1854 - 1930) - Comstock was a pioneer in the field of nature education. She is famous for being one of the first to bring her students and other teachers out-of-doors to study nature. She wrote Handbook of Nature Study , in 1911. First female professor at Cornell; In 1923, she was nominated by the National League of Women Voters as being among the twelve greatest women of the country. In her Handbook she writes: "For some inexplicable reason, the word animal, in common parlance, is restricted to the mammals. As a matter of fact, the bird, the fish, the insect, and the snake have as much right to be called animals as the squirrel and the deer."


Congeners - The species of birds that are all in the same genus. The Black-bellied Plover (Pluvialis squatarola) and Pacific Golden Plover (Pluvialis fulva) are congeners in the genus Pluvialis. But the other plovers, Semi-palmated (Charadrius semipalmatus), Snowy (Charadrius alexandrinus), Killdeer (Charadrius vociferus) and Mountain (Charadrius montanus) are congeners of a different genus, Charadrius.


Convergent Evolution - "The independent evolution of structural or functional similarity among unrelated groups." Introduction to California Birdlife, Jules Evens and Ian Tait.. For an example look at the Tri-colored Heron and the Green Heron. Two different species that have similar hunting techniques in the same habitat.


Coues, Elliot - (1842 - 1899) - American ornithologists. Coues Flycatcher (now named Greater Pewee, Contopus pertinax) was named after him. Author of a variety of books including Birds of the Northwest and New England Birdlife. Some of his writing can be viewed in the natural history accounts of these species: Snow Goose, Gambel's Quail, Pacific Loon, Tri-colored Blackbird,


Courtship - The behavior that various animals (usually males) utilize to attract a mate.


Crustaceans - Arthropods such as crabs, lobsters, shrimp; have a hard outer shell.


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DDT - dichlorodiphenyltrichloroethane - A pesticide that was responsible for eradicating malaria, but is also thought to be responsible for egg thinning amongst fish-eating birds such as the Osprey and the Bald Eagle. When parent birds sat on the eggs, the eggs broke because of the thin shell. It was banned during the 1970s.


Darwin, Charles - (1809 - 1882) - English naturalist who is considered to be most responsible for recognizing the forces of evolution. His book The Origin of Species was published in 1859.


Dawson, Leon - (1873 - 1929) - Ornithologist who specialized in studying the birds of the Northwest states and wrote Birds of Washington; also wrote a three volume work, Birds of California. Some of his writing can be viewed in the natural history accounts of these species: Vermillion Flycatcher, California Quail, California Condor, Brewer's Blackbird, Marsh Wren, Hermit Thrush, Townsend's Solitaire,


Decurved - Describes a beak that is curved down as in the Long-billed Curlew, Whimbrel, White Ibis etc.


Desert - One of the types of biomes, marked by limited water, and seasonal heat and cold. "The geographical, geological, and other natural history features of our desert domains are so varied and with them are bound up so many entrancing problems that fifty years of intimate acquaintance and wide travel over the arid Southwest have not desiccated my ardor for continued study and wide wanderings nor lessened my eagerness to lead others to the heart of my kingdom of joy. The question 'What is a desert?' cannot be answered without facing many difficulties. The term desert does not necessarily imply paucity of life, continuous heat, marked lack of moisture, or the presence of sandy wastes, although all these phenomena may occur. Even meagerness of rainfall is not always the deciding factor in the making of deserts but is only one of a combination of factors. Rocky or alkaline soils and continuous winds are features which play no minor role. For our present purposes, deserts may be defined as places of high, diurnal, summer temperatures, with more or less steady, drying winds and slight rainfall (generally under ten inches a year) and that unevenly and, from the standpoint of all but specialized plants and animals, often very unsatisfactorily distributed." Edmund C. Jaeger, The California Deserts.


Desertification -  A term used to indicate a habitat that has been degraded. It seems to be used by people who do not appreciate the true quality of a desert. A desert, as seen in California, Nevada, New Mexico etc. is a natural habitat that is inhabited by many species that have spent thousands of years developing adaptations to a web of other creatures who have adapted to the desert. The Yucca Moth and the Yucca have a very specialized relationship. Anybody who has visited the deserts, read Edmund Jaeger, spent anytime studying the inhabitants of a true desert, realize the biotic wealth of the area. The Cactus Wren, Road runner, Rock Wren, Scott's Oriole, Poorwill, Costa's Hummingbird, Ladder-backed Woodpecker, Black-tailed Gnatcatcher, and so many other animals and plants do not inhabit a wasteland. They inhabit the desert. The migratory birds that stop in at the desert oasis for a drink of water appreciate the opportunity as they fly from South America to breed in our northern forests. If we wish to indicate a habitat that has been destroyed through human activities then we should just call it a wasteland; a habitat that has been wasted.


Diptera - Large order of insects; true flies including house flies, and blood sucking flies such as mosquitoes and midges, etc.


Disease - (From A New Dictionary of Birds (1964) edited by Sir A. Landsborough Thomson and published by the British Ornithologists Union; The Disease essay is written by Arthur Ramsden Jennings). (Below is a portion of the Disease essay written by Arthur Ramsden Jennings) "ill health in any of the many forms from which birds, like all other animals may at times suffer. The causes of disease may be divided into immediate (or exciting) causes and predisposing causes. The chief predisposing factors in bird diseases are bad environmental conditions and adverse changes in food supply.

Climatic changes and food supply are often linked. The bird's resistance to disease may be lowered by poor nutrition or by sudden changes in the temperature; thus abnormal heat or abnormal cold may cause heavy losses either directly or by predisposing to infectious disease. Sustained wet and cold weather is liable to bring on diseases of the lungs, which are a common source of trouble in chicks, especially amongst the nidifugous species.

Some of the more commonly encountered diseases of wild birds, other than those due to metazoan parasites, are described below. These conditions also occur in domestic and caged birds, but the emphasis here has been placed on the free-living wild bird.

  • Aspergillosis - This disease is due to infection with a mould, usually Asperfillus fumigatus, which is commonly present in decaying vegetable matter.
  • Botulism - An anaerobic bacterial organism, Clostridium botulinum Type C, produces a very powerful exotoxin that is responsible for a serious type of food-poisoning in many species of animals, including birds and man.
  • Candida albicans Infection - This fungus sometimes causes disease of the mouth and crop of birds, a condition called 'thrush' or 'canker' by the bird-keeper. In young birds it sometimes cases serious losses.
  • Deficiency diseases - Lack or imbalance of amino-acids, proteins, carbohydrates, fats, minerals, water, and vitamins may lead to disease.
  • Encephalitis - Inflammation of the brain occurs in birds, and one specific form of this is due to a virus.
  • Erysipelas Infection - The micro-organism Erysipelothrix rhusiopathiae usually produces a fatal septicaemia. Most species of mammals, birds and fishes seem to be susceptible to infection with this organism which can live for long periods in the soil and probably gets into the body through small abrasions and wounds.
  • Fowl Leucosis - The term 'leucosis complex' refers to a group of diseases characterized by an abnormal production of the white blood cells and consequent changes in the organs and tissues.
  • Fowl-plague - This is a most serious virus infection of domestic fowls, but most other birds are fairly resistant. The disease spread rapidly in fowls and produces a high mortality.
  • Fowl-pox - This is a virus infection of the skin, especially of the head and feet, of birds. it is a common disease and has been recorded in many species.
  • Lead Poisoning - This is common in waterfowl in America and is a serious source of loss. (Since the publication of this book, lead shot has been outlawed.)
  • Newcastle Disease - Caused by a virus, this is one of the most serious diseases of domestic poultry and has a world-wide distribution.
  • Pasteurellosis - Pasteurella pseudotuberculosis is a common pathogen of wildlife.
  • Protozoal Infections - Many protozoa parasitise birds, but few of them are pathogenic. They are to be found in many tissues of the body.
  • Psittacosis - This is a disease caused by a very large virus, and epidemics of psittacosis have been described in captive and free-living wild birds.
  • Quail Disease - Enzootics of a highly fatal disease in the American Bobwhite Colinus virginianus and some species of grouse (Tetraonidae) have been described.
  • Salmonellosis - Infections of birds with Salmonella organisms are common and important problems in the poultry industry.
  • Tuberculosis - The avian type of Mycobaterium tuberculosis is a common cause of tuberculosis in birds, which become infected by ingestion.
  • Tumours - Neoplasms (malignant new growths) are common in birds, and many different forms occur.
  • Vesicular Dermatitis - This term is applied to a skin disease that is due to one or more viruses and occurs in several species of wild birds, including the Manx Shearwater (Puffinus puffinus) and other water birds.


 Distribution - How various species are scattered about the globe. Some species have a very narrow distribution. In the United States theLimpkin is only found in Florida. Other species such as the Great Blue Heron are found in all 50 states. Species such as the House Finch over the past 40 years has been gradually increasing their distribution from the western US to include the eastern US.

From A Dictionary of Birds: "The distribution of species or other categories considered in broad terms of range. Since local abundance and local distribution within the limits of the range depend on ecological factors, the range may be limited by the same factors, such as climate or its effect on habitats, habitat availability, or presence of competitors, predators, or prey. Ecology and Zoogeography thus have broadly overlapping interests. The range boundaries may, however, also be set by evolutionary history, plate tectonics, effective dispersal barriers, or the different dispersal abilities of species.

"Zoogeographical studies address themselves to various aspects of geographical distribution. the time scale examined may vary from a static 'snap-shot' view of the present distribution to millions of years, and the geographical focus of interest may range from global distribution to distribution on islands or to dynamics of a portion of the range boundary. In addition, the emphasis may be qualitative or quantitative.

"In terms of scientific research and the philosophy of science, a distinction can be made between descriptive, analytic, and predictive zoogeography. The descriptive view records facts of distribution , past or present. Analytic zoogeography attempts to relate results of descriptive studies to various causes, ecological or historical. Predictive zoogeography uses theoretical, often mathematically formulated, models in order to derive predictions on patterns of geographical distribution. In recent years, analytic and predictive aspects of zoogeography have developed rapidly, and, at the same time, quantitative approaches and population biology have been increasingly used in order to understand distribution patterns.


DNA - The chemical code that determines an individual's uniqueness. All vertebrates are the result of a combination of their parent's DNA. (See classification)

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Drinking - From the Cambridge Encyclopedia of Ornithology "Drinking is necessary only if the food does not provide enough water to balance any loss that occurs by excretion or evaporation through the lungs - birds do not sweat and do not normally produce liquid urine. The frequency of drinking depends on the type of food and the bird's ecology; most seed-eaters need to drink at least once a day and may take in about 10% of their body weight, but some small birds of arid regions, such as the Zebra Finch and Budgerigar, can survive for many months on dry seeds without drinking or losing body weight. Presumably they can adequately supplement low dietary moisture with water produced internally through metabolism.

"The method of drinking varies. 'Sipping and tilting' is the commonest - the bill is dipped in the water, a sip taken and the head raised so that water trickles down the throat by gravity.

"Marine species have particular problems with drinking in that they take in salt with their food or drinking water. Small species are more sensitive to salt stress than larger ones and most marine ducks, for instance, are quite big. The salt is eliminated by the excretion of a concentrated solution through glands that have been inherited from the birds' reptilian ancestors and are situated just beneath the skin above the eyes. A duct from each gland leads into the nose from which saline fluid flows down the bill and is removed when the bird shakes its head."

Dusting - A type of care behavior in which certain species of birds roll their bodies in dirt to help in their battles with external parasites. Examples of this can be seen in the House Sparrow and the California Quail.


Eclipse plumage - A post breeding plumage that occurs in some species; often refers to plumage that male ducks have between their breeding plumage and their non-breeding plumage; some species of ducks are unable to fly during this plumage.


Ecology - Study of the interrelationships between plants and animals with their physical environment. When we read in the A.C. Bent text for the Indigo Bunting how the bunting's population increases in areas of secondary growth, we are studying the species from an ecological perspective (Bent uses an excellent article written by the ornithologist James Bond). The word, ecology, has been misunderstood by many people. Ecology is neither good nor bad. It is a science used to study the relationship between organisms and their physical environment. From A New Dictionary of Birds - portions of the Ecology essay written by Robert MacArthur: the study of plants and animals in relation to their environment... As regards birds, it is well known that each species breeds and spends the winter, respectively, in characteristic areas of the earth; these areas, which in some instances are the same, form the geographical distribution of the species. Within the areas, the species will occupy only certain habitats; and within the habitats, each species has a characteristic behavior and abundance. The explanation of these patterns of distribution and abundance is the main problem of avian ecology.


Ecological niche -


Ecosystem - The totality of factors of all kinds that make up a particular environment.


Ecotone - The edge of a habitat; quite often the edge between two different habitats The number of species is generally pretty high along an edge.


Endangered - When a population of a species is at a point that the species may not exist for too many more years, it is determined to be an endangered species. Examples of endangered species would be: California Condor, Clapper Rail. Some members of the Endangered List have been removed such as the Bald Eagle, and the Brown Pelican.


Endemic - Found only in certain areas. The Yellow-billed Magpie is only found in the state of California, so it is endemic to California. The American Magpie is found in many states so it is not endemic.


Ethology - The study of animal behavior under natural conditions. Niko Tinbergen, Konrad Lorenz and Karl Von Frisch are considered the originators of this science, and they received the Nobel Prize in Medicine in 1973 for their work.


Evolution - The process that leads to speciation. Evolution is the central theme of the study of biology. From A New Dictionary of Birds: "The theory which states that the different kinds of living tings have been produced by descent with modification from previously existing forms, not by each one being created separately with its present characters."


Evolution of birdlife - (From The Birdwatcher's Companion )

Major Trends/Events
Evolution of Birdlife
Paleozoic Era: 600 million to 225 million yhears ago

Evolution of life from earliest marine plants and invertebrates to presence of all current invertebrate classes plus fishes, amphibians, and reptiles. Reptiles emerged in the Pennsylvanian (late Carboniferous) Period (about 300 million years ago) and by the end of the Permian Period (280 to 225 million years ago) had greatly diversified.

Mesozoic Era: 225 million to 195 million years ago
Triassic Period: 225 million to 195 million years ago

North American climate mild; deserts extensive. forests of conifers and cyads; tree ferns and horsetails abundant. Amphibians decline; dinosaurs (including tecodonts) dominant by end of period.

No birds
Jurassic Period: 195 million to 135 million years ago

Sierra Nevada and Cascades araise. Climate mild; deserts widespread. Cycads dominatn plants; confiers still abundant. Age of Reptiles: present on land, in sea, and in air; great dinosaurs.

Archeopteryx: first known bird.
Cretaceous Period: 135 million to 70 million years ago

50 percent of North America under water; extensive limestone deposists/fossil beds laid down in West. Rockies arise. Climate turns cold late in period. Flowering plants appear; deciduous forests become dominant; sequoias widespread. Tyrannosaurus and other dinosaurs thrive at first, becoming extinct by end of period. Marsupials and primitive placental mammals evolve.

Apatornis, Baptornis, Hesperonis, and Ichthyornis. Also birds resembling modern loons, cormorants, ibises, rails, and sandpipers.

Cenozoic Era: 70 million years ago to present.
Tertiary Period
Paleocene/Eocene Epoch 70 million to 38 million years ago

Early mountain building followed by erosion; much of Atlantic and Gulf lowlands submerged. Seed-bearing plants continue dominant. Early 1-foot high horse (Eohippus), camels, elephants, dogs, cats evolve.

Few bird fossils from Paleocene: first hawks, also loons, tropicbirds, vultures, gulls, and terns. Eocene sees major evolution of birdlife, with nearly all known orders established by its close: albatrosses, pelicans, ibises, flamingos, grouse, pheasants, cranes, auks, cuckoos, owls, kingfishers, and a few passerines (e.g., starlings); also Diatryma, Neocathartes.

Oligocene Epoch: 38 million to 26 million years ago

Coastal lowlands emerge; active vulcanism along Pacific coast. Climate continues mild. Modern-type forests. Mammals dominant, especially cat and dog families; also three-toes horse, mastodon, antrhopoid ape.

First known grebes, shearwaters, boobies, storks, turkeys, limpkins, plovers, parrots, pigeons, nightjars, swifts, Old World warblers, and ploceid sparrows. A few genera of present-day birds appear. Many species of cranes and rails.

Miocene Epoch: 26 million to 12 million years ago

Sierras and Rockies rise again. North America at first very warm, cooling toward end. Forests reduced, plains and deserts arise. More modern tree species evolve. Golden Age of Mammals: great diversity of camels, great ape in Europe.

Most modern bird families probably exist; more modern genera evolve.

Pliocene Epoch: 12 million to 2-3 million years ago

Last lifting of Appalachians, Rockies, Sierras, Cascades. Climate continues to cool. Mastodons migrate from Old World to New; forerunner of modern horse; gorilla; beginning of Old Stone Age.

Birds reach maximum diversity; emergence of many modern genera and species. Moas, ostriches, rheas, tinamous, larks, swallow, nuthatches, emberizids, and (perhaps) woodpeckers appear.

Quarternary Period
Pleistocene Epoch: 2-3 million years ago to 10 thousand years ago

Ice Age: glaciers cover northern half of North America 4-5 times, greatly altering earth's surface;Great Lakes, many other modern geological features formed. Climate cold except for tropics. Four species of elephants, camels, saber-toothed tider in North America early in epoch; many large mammals and other forms dies out with advance of ice. Rise of Homo.

All modern birds in existence by end of epoch. Glaciation causes: demise of some large, ancient forms; division of populations in North America, promotoing speciation; retreat of species from North, perhaps leading to evolution of migration.


Extirpated - Extinct from a particular region. The Sharp-tailed Grouse has been extirpated from California.

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Family - The classification level between Order and Genus. Depending on which system you follow there are approximately 143 families of birds in the world and 67 families of birds in the United States. In the US Recurvirostidae is the family that includes the two species, American Avocet and the Black-necked Stilt. From A New Dictionary of Birds: "A primary taxonomic category (or a particular example therof), being a subdivision of an order and a grouping of genera." (Kingdom, Phylum, Class, Order, Family, Genus, Species)


Feather - There are three main types of feathers on a bird's body: down, contour, and flight. From A New Dictionary of Birds: "The component unit of the plumage and a structure outstandingly and uniquely characteristic of birds as a class. "

From Wikipedia: Feathers are among the most complex structural organs found in vertebrates: integumentary appendages, formed by controlled proliferation of cells in the epidermis, or outer skin layer, that produce keratin proteins. The ß-keratins in feathers, beaks and claws — and the claws, scales and shells of reptiles — are composed of protein strands hydrogen-bonded into ß-pleated sheets, which are then further twisted and crosslinked by disulfide bridges into structures even tougher than the a-keratins of mammalian hair, horns and hoof.

Feathers insulate birds from water and cold temperatures. Individual feathers in the wings and tail play important roles in controlling flight. These have their own identity and are not just randomly distributed. Some species have a crest of feathers on their heads. Although feathers are light, a bird's plumage weighs two or three times more than its skeleton, since many bones are hollow and contain air sacs. Color patterns serve as camouflage against predators for birds in their habitats, and by predators looking for a meal. As with fish, the top and bottom colors may be different to provide camouflage during flight. Striking differences in feather patterns and colors are part of the sexual dimorphism of many bird species and are particularly important in selection of mating pairs. The remarkable colors and feather sizes of some species have never been fully explained.

Feather tracts - The bird's body is not covered with feathers, but instead has tracts from which the feathers come from and cover the entire body. In between the tracts is bare skin.


Feeding - The process of acquiring food. Some animals specialize in particular types of food. Animals that specialize in fish are called piscivorous; animals that specialize in insects are called insectivorous. Omnivorous describes the many species of animals that feed on what is available. The American Crow is omnivorous.

  • Insectivorous - Refers to animals that primarily eat insects. Flycatchers and swallows are good examples of insectivorous birds.
  • Piscivorous - Animals that eat primarily fish, such as the Osprey.
  • Nectivorous - Animals, such as the hummingbird, that feed primarily on nectar that they get from flowers.
  • Granivorous - Animals that eat primarily seeds such as sparrows and finches.
  • Frugivorous - Animals that feed largely on fruit. Birds that are frugivorous include orioles, tanagers (Summer Tanager) jays (Green Jay) etc.
  • Herbivorous - Animals that eat plants such as grouse and ptarmigan
  • Omnivorous - Refers to animals that eat everything. They eat plant food, fish, mammals, birds, etc. and will scavenge food. Gulls (Western Gull, etc.) are good examples of omnivorous feeders; also the Great-tailed Grackle. Most species are more specific about what they eat.  

From The Birdwatcher's Companion "Some of the methods and 'tools' by which birds search out and obtain their food are more complex and/or less obvious to the casual observer and merit a brief discription.

"Flight Mannerisms - An unusually slow flight has evolved in the harriers and the Turkey Vulture as a means of effectively scanning large areas for their preferred prey. Some seabirds, most buteos and vultures soar on rising air currents for a similar purpose. And the American Kestrel, some hawks and kingfishers hover in midair, keeping their heads stationary to watch for movements of small, quick prey below.

"Nightjars - have small bills but enormous gapes (2 inches fully opened in Chuck-will's-widow) and fly through the air with their mouths open, swallowing numbers of insects (from tiny flies to large beetles) and even an occasional small bird. It has been widely suggested- but not conclusively shown - that the long, stiff, modified feathers (rictal bristles) that border the upper half of the gape in most nightjar species serve to enlarge their effective 'funnel' and also detect the presence of insects flying nearby in the dark. The latter hypothesis gains some support in the fact that the nighthawks (genus Chordeiles), which on the average fly during daylight hours more frequently than other nightjars, lack rictal bristles.

"Canopy Feeding - is practiced by some heron species and consists of raising the wings to create a shadow over shallow water. This may serve the dual purpose of attracting fish and cutting surface glare for the heron.

"Foot movements - are used in several bird families to flush prey within reach. Herons and some shorebirds stir the bottom in shallow pools and pick up any disturbed invertebrates. The characteristic 'spinning' of phalaropes is an elaboration of this technique. Some gulls are reputed to 'paddle' the earth with their feet to bring earthworms to the surface. And 'foot flushing' is also recorded in some ground-feeding songbirds.

"The Long Tongues - of most woodpeckers and hummingbird species can be extended into a tree cavity or flower calyx as much as several inches with the aid of an extendible bone and muscle structure known as the hyoid apparatus. This mechanism is attached at the base of the tongue, coils around the back and top of the skull, and is anchored at the nostrils. The actual tongues of these birds bear a variety of specializations - barbs, brushes, grooves, saliva - that help capture and/or swallow particular food types.

"Wing Flashing - i.e., lifting the wings suddenly, is apparently used by species of herons and mockingbirds to startle aquatic life and insects into motion, so that they can be seen and eaten. Mockingbirds also use this gesture in confrontations with snakes and other threatening situations.

"The Bills of Avocets - are strongly recurved toward the tip and vertically flattened. when a bird lowers its bill into the water, the upturned third of the bill becomes parallel to the surface and is swept rapidly back and forth amidst the surface algae or in bottom sediment and vegetation. When live organisms (small fish, mollusks, crustaceans, etc.) are felt by the bill, the mandibles close on the prey.

"The Bills of Spoonbills - are strongly flattened vertically and widened into a spatula shape at the tip. The interior of the 'spoon' is lined with sensitized tissue. Spoonbills feed by wading in shallow water and sweeping their partially opened bills from side to side in bottom sediment and vegetation. When live organisms (small fish, mollusks, crustaceans, etc.) are felt by the bill, the mandibles close on the prey.

"Skimmers - are unique in having a lower mandible which is significantly longer than the upper - an adaptation to an equally unique method of feeding. The birds fly low over calm water (often at dawn, and dusk and in flocks) and 'shear' the surface with the tip of the lower mandible, which is laterally flattened to nearly razor sharpness. When a fish or other edible object is encountered by this blade, the upper mandible closes down on it instantly. Skimmers will often retrace a stretch of water they have just 'plowed', apparently to take advantage of fish which rise to investigate the initial disturbance."


Fledge - (fledged, fledgling) - When a bird has left the nest it has fledged (White-crowned Sparrow). While it is in the nest it is a nestling. As a fledgling it is out in the world though it may still be fed by its parents (Elegant Tern) (Bullock's Oriole). This is probably the most dangerous period of time for a young bird. The relationship between the adult bird and the young varies with each different species during this time.


Foraging - The different behavior used by birds to find food. Basically there are two main categories of foraging: feeding from the air and feeding from a surface. Feeding from a surface can be classified as gleaning (Yellow-rumped Warbler), reaching (Little Blue Heron), hang gleaning, lunging. Feeding from a surface to under the surface can be classified as probing (Brown Creeper), gaping, pecking (woodpeckers), chiseling, hammering (woodpeckers, chickadees, titmouse), flaking (woodpecker), prying (woodpecker) and scratching. Aerial maneuvers can be defined as sallying, flutter chase, flush, pursue, hover gleaning (Blue-gray Gnatcatcher), and screen.


Forbush, Edward Howe - (1858 - 1929) - Author of Useful Birds and Their Protection, published by the Massachusetts State Board of Agriculture (1907). Some of his writing can be viewed in the natural history accounts of these species: Trumpeter Swan, Chipping Sparrow, Black-bellied Plover, Winter Wren, Golden-crowned Kinglet, Starling, Yellow-rumped Warbler, Black-throated Green Warbler, Chestnut-sided Warbler, Northern Waterthrush, Scarlet Tanager, Purple Martin,

From Wikipedia: Edward Howe Forbush (April 28, 1858 – March 7, 1929) was a noted Massachusetts ornithologist and a prolific writer, best known for his book Birds of New England. Born in Quincy, Massachusetts, in 1858, he was a precocious naturalist. His family moved to West Roxbury, when he was seven. As an older child, he conducted field studies of area wildlife and also studied taxidermy. Once again, his family moved to Worcester, where he became a member of the Worcester Natural History Society, and began to publish the results of his studies. At the age of sixteen he was appointed Curator of Ornithology of the Society's museum. When he was nineteen, he mounted an expedition to Florida — this would be the first of many trips he took around the United States to study birds. In 1893, Forbush was appointed Ornithologist to the Massachusetts State Board of Agriculture. His primary studies at this time were "economic ornithology" — that is, determining whether a given species of bird was beneficial or detrimental to agriculture. In 1908 he became the Massachusetts State Ornithologist. He was a founder of the Massachusetts Audubon Society. He was also first president of the Northeastern Bird-Banding Association (now the Association of Field Ornithologists). His work "Birds of Massachusetts (and Other New England States)" is a three-volume set of books published 1925–1929 by the Massachusetts Department of Agriculture. Title notwithstanding, it was and remains a valuable reference regarding not just New England birds but also in regard to ornithology of the Northeast and farther afield. He died in Westboro in 1929. In 1931, The Forbush Bird Club of Worcester, Mass., was established in his memory.


 Gause's Rule of Non-Competition - From A Dictionary of Birds (Campbell and Lack, Eds): "In 1934 G.F. Gause wrote: 'As a result of competition two similar species scarcely ever occupy similar niches, but displace each other in such a manner that each takes possession of certain peculiar kinds of foods and modes of life in which it has an advantage over its competitor'. Gause's rule is often paraphrased as: 'Species with similar (or the same) ecological niches cannot coexist'; and as its corollary 'Coexisting species differ in their ecology.' Gause's rule is useful as a general statement: but it is not a testable hypothesis in normal scientific terms, because its reasoning is circular. if species coexist, they must be sufficiently different: if they do not coexist, they are too similar. Unless the terms 'similar' and 'different' can be made more precise, there is no way out of this impasse."


Genus - The level of classification between Family and Species. Within the family Anatidae (the Ducks, Geese, Swans) there is the genus Anas which includes the Mallard, (Anas platyrhynchos) Shoveler (Anas clypeata) and teals and other ducks. This genus is quite different from the genus Mergus which includes the Red-breasted Merganser (Mergus serrator) and the Common Merganser, but interestingly does not include the Hooded Merganser. By studying genera (plural of genus) a birdwatcher can begin to understand some of the subtle differences between birds. By noticing that the Hooded Merganser and the Red-breasted Merganser belong to different genera one would want to understand what the difference is between the two birds. (Kingdom, Phylum, Class, Order, Family, Genus, Species)


 Grasslands - "Grassland biomes are large, rolling terrains of grasses, flowers and herbs. Latitude, soil and local climates for the most part determine what kinds of plants grow in a particular grassland. A grassland is a region where the average annual precipitation is great enough to support grasses, and in some areas a few trees. The precipitation is so erratic that drought and fire prevent large forests from growing. Grasses can survive fires because they grow from the bottom instead of the top. Their stems can grow again after being burned off. The soil of most grasslands is also too thin and dry for trees to survive. " (From, Grasslands , done by The West Tisbury School is a K-8 school located on Martha's Vineyard, an island approximately 6 miles off the south coast of Massachusetts. It is part of the Up-Island Regional School District that is presently composed of the towns of Aquinnah, Chilmark & West Tisbury.)


Grinnell, Joseph - (1877 - 1939) American ornithologist who held the job of Director of the Museum of Vertebrate Zoology at the University of California at Berkeley, and specialized in studying the birds of California. Author of The Distribution of the Birds of California (with Miller) and Philosophy of Nature, a posthumous gathering of his essays in 1943 amongst other books. Some of his writing can be viewed in the natural history accounts of these species: Greater Scaup, Band-tailed Pigeon, Black-bellied Plover, Mountain Chickadee, California Thrasher, Scott's Oriole, Cassin's Finch,



Habitat - Where an organism lives. For some types of birds like the House Sparrow, the habitat needs to be near people. For other species such as the Clapper Rail there are very specific requirements in the type of habitat it can live in. Quite often habitats are very specific to different species in the same family. The Brown Pelican needs salt water while the White Pelican is almost always in fresh water. The American Dipper is usually found in mountainous streams of fast moving water. There are also species that change habitats during a year. The Common Loon spends its non-breeding time mainly in salt water, while it breeds entirely on freshwater lakes. The Wrentit is only found in chaparral habitat, while the American Crow is found in most every habitat. A bird's habitat is different from its range.

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Hemiptera - Large order of insects that includes the true bugs.


Herbivorous - Animals that eat primarily plants (i.e., Blue Grouse, White-tailed Ptarmigan)


Heermann, A. L. (1827 - 1865) "Adolphus Lewis Heermann was a surgeon-naturalist in the Army of the United States who worked closely and effectively with Baird on the Pacific Railroad Surveys. Heermann was born about 1827, the son of a doctor in the United States Navy. It is recorded that both he and his brother were ardent naturalists throughout their youths. He was elected to the Philadelphia Academy in 1845 and graduated from the University of Maryland Medical School in 1846." From, Words for Birds by Edward S. Gruson. The Heermann's Gull was named after A. L. Heermann.


Hoffman, Ralph - Author of Birds of the Pacific States; my first field guide to the birds of the Pacific states and a great pleasure to read. Some of his writing can be viewed in the natural history accounts of these species: Gray Flycatcher, Tri-colored Blackbird,


Huxley, Julian S. (1887 – 1975) - (From Wikipedia) "Sir Julian Sorell Huxley, FRS (June 22, 1887 – February 14, 1975) was a British biologist, author, Humanist and internationalist, known for his popularisations of science in books and lectures. He was the first director of UNESCO and was knighted in 1958." Author of The Courtship Habits of the Great Crested Grebe.

Huxley was part of a distinguished family. His brother was the writer Aldous Huxley, and half-brother a fellow biologist and Nobel laureate, Andrew Huxley; his father was writer and editor Leonard Huxley; and his paternal grandfather was biologist T. H. Huxley, famous as a colleague and supporter of Charles Darwin. His maternal grandfather was the academic Tom Arnold, and great-grandfather Thomas Arnold of Rugby School. Some of his writing can be viewed in the natural history accounts of these species: Little Blue Heron,


Hybrid - When two different species mate and have offspring. Their offspring are almost always unable to have their own babies. Part of the decline of the Black Duck is attributed to their hybridizing with Mallards. The same fate is anticipated with the Spotted Owl and the Barred Owl. A hybridization between an American Avocet and a Black-necked Stilt can be seen in this photo. From Introduction to California Birdlife by Jules Evens and Ian Tait: "Hybridization among closely related species confounds the definition of species but also sheds light on the nature of evolution among birds. When closely related, or recently diverged, species of the same genus (congeners) come into contact, hybridization may occur. Most of the species that do interbreed belong to a superspecies complex and though they may interbreed to a limited extent in overlapping portions of their ranges, they are behaviorally isolated. (Pacific-slope and Cordilleran Flycatchers are sympatric in the northern Siskiyou Mountains, but they are isolated by behavioral differences.) Species pairs of California birds that are prone to limited hybridization include: Red-breasted Sapsucker x Red-naped Sapsucker; Townsend's Warbler x Hermit Warbler; Clark x Western Grebe, Nuttall's x Ladder-backed Woodpecker and possibly Nashville x Virginia Warbler. In contrast, Western Gull x Glaucous-winged Gull hybrids are rather common, though mostly overlooked. Occasionally, hybrids are found that are the product of western (Californian) and mostly eastern species: Lazuli x Indigo Bunting; Black-headed Grosbeak x Rose-breasted Grosbeak; and sparrows of genus Zonotrichia, the White-crowned Sparrow, Golden-crowned Sparrow, and White-throated Sparrow."


 Hybridization, Zone of Secondary - From A New Dictionary of Birds: "An area in which two closely related forms make contact and freely interbreed, having earlier differentiated under conditions of geographical (or ecological) isolation (see speciation). This seems to be the only way in which such a situation could arise, as without a period of isolation the gene flow would either prevent differentiation or would limit it to clinal variation. One must therefore postulate the earlier existence of a barrier that has since broken down or been surmounted.

This may sometimes be due to human activity, e.g. in cutting virgin forest or in planting trees at intervals across open prairie. The disappearance of a barrier would, broadly speaking, create one of three types of situation according to the extent to which differentiation had meanwhile proceeded. At one extreme, contact between the two forms would not result in any regular interbreeding - there would in fact be no zone of hybridization at all, and the two forms would obviously have become 'good' species. At the other extreme, if there was no selection against the hybrid forms, the genetic results of interbreeding would spread in both directions from the area of contact, so that the two forms would ultimately be merged again in a single cline in which the two previously differentiated forms would lose their identity; this would be proof that the two stocks had not become irrevocably committed to separate lines of evolution.

Between these extremes there is the situation in which there is selection against the hybrids, which are in some way at a disadvantage as compared with the parent stocks. In these circumstances the two forms retain their identity in their main areas, and intermediates are restricted to the zone of contact; the genetic results of interbreeding are prevented from spreading into the two main populations. Theoretically, the conditions of natural selection might alter is some way and the situation is thus not absolutely stable; apart from that possibility, the two stocks have clearly established a good measure of evolutionary independence and could be regarded as separate species notwithstanding the regular occurrence of intermediates in a limited zone.

A classical case is that of the Carrion Crow and the hooded Crow, two closely similar birds with a striking plumage difference. In their breeding areas they more or less divide the Palaearctic Region between them, with contact along a line across the Highlands of Scotland, along a line approximating to that of the River Elbe, and along lines in central and eastern Asia. These lines correspond with zones of hybridization, in which obvious intermediates are common; elsewhere each kind preserves its distinctive character, although further divisible into geographical races. Similarly, in North America, the Blue-winged Warbler, and the Golden-winged Warbler regularly interbreed where their ranges overlap.

A much more complex situation has been described by Sibley and his associates in respect of the Rufous-sided Towhee and the Collared Towhee. These two otherwise similar emberizids are strikingly different in plumage (in both sexes). Both are widespread in Mexico (and the former also north to southern Canada) but are there altitudinally and ecologically separated in their breeding distribution. Local areas of contact are therefore numerous, but the situation differs from one to another. In some localities the two forms exist together without interbreeding, while elsewhere interbreeding is the rule. Certain areas are thus inhabited wholly by intermediates, of which some populations show a preponderance of this or that element while others show a more or less equal balance. Others are inhabited by pure stocks of one species or the other - and a few places, as already noted, by pure stocks of both. There is thus in some localities an instability in the reproductive isolating mechanisms that in others suffice to keep the two forms distinct.

As Sibley (C.G.) points out, the result of selection against hybrids is to eliminate the descendants of those members of the parental stocks in which the reproductive isolating mechanisms are weakest; there is thus, in effect, a 'reinforcement' of the isolating mechanisms, which may lead to a reduction in the number of hybrids produced. This may happen quite rapidly, so that a new situation due to the breakdown of a barrier may soon become stabilized. Vaurie has described how the Azure Tit in the latter part of the nineteenth century, extended its range rapidly from Siberia into the range of the Blue Tit in Europe. The two species interbred freely at first, but the incidence of hybridization soon waned. Although - the Siberian Tit having in part retracted its range - there is still an area of overlap, hybridization is now only occasional.

The whole question is one of great interest; and when the process of evolution is as rapid as in some of the instances cited, the opportunities for study are invaluable."


Hymenoptera - Very large order of insects that includes bees, wasps, ants (see anting), sawflies, etc. Over 100,000 species.

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Incubation - The period of time from when the eggs are laid to when they hatch. Generally, smaller birds have shorter incubation times, larger birds have larger incubation times.


Indicator species - There are species that have very specific habitat requirements. The population of these species can be used as one type of monitoring to determine the health of that specific habitat. If the population is thriving then the habitat is healthy. If the population is doing poorly then questions need to be asked. The Clapper Rail is only found in a salt water marsh and has a restricted diet of other animals only found in the salt marsh; it is an indicator species of a salt marsh. The Dipper feeds in fast moving fresh, clear water and so can be considered an indicator species of a watershed. The Spotted Owl is an indicator species of old growth forests. The Sage Grouse is an indicator species of sage habitat. The Brewer's Blackbird is not an indicator species because it can be found in a multitude of habitats. Link to a report on the Tree Swallow as an indicator of atmospheric contamination. From A Dictionary of Birds: "Indicator species: species whose ecological requirements are such that their presence more or less guarantees the existence of particular environmental conditions. It may then be easier to observe the presence or the absence of the indicator species than to measure the environmental conditions themselves."



Insects - Invertebrates of the class, Arthropod, that have six legs and three body parts: head, thorax, abdomen. Over 700,000 species. Includes beetles, moths, butterflies, wasps, ants, bees, flies, mosquitoes, true bugs, aphids, cockroach, grasshoppers, etc. People who study insects are entomologists. Insects on the WWW. There are reports of a few insects that eat birds such as the Preying mantis eating small birds (hummingbirds),


Introduced Species - Species that are brought over to an area generally by human forces. The Starling was brought to the United States by a person who wanted to have the birds that are in Shakespeare's plays present in America. This species has increased in number in the hundred years it has been here and has caused considerable damage. Other examples of introduced species would be the English Sparrow, and the Common Pigeon. The pigeon was native to Europe and brought to North America.


Invertebrates - Animals without backbones. It is difficult to over estimate the importance of invertebrates to the rest of the living world.

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Iridescent Colors - Colors that result from light waves being interfered with. This effect is seen often in hummingbirds and also on various blackbirds, members of the crow family like the Common Raven, and ducks such as the Bufflehead.


Juvenal - The plumage that a bird has after leaving the nest. This is shown on the page of the Western Gull. the White-crowned Sparrow.


Juvenile - A bird while it wears its juvenal plumage. This period of time can vary for different species. Many songbirds reach adult plumage within a few months while other species such as gulls and hawks take a few years before they obtain adult plumage.


Keystone Species - A certain key species playing a major role that is out of proportion to its abundance in the community. A keystone species has an effect on the overall diversity of a habitat. If you take a keystone species out of an area the result is a major change to that area. Red-naped Sapsucker is a keystone species because of the number of other species that are dependent on the sap and insects that they get from the holes that the sapsucker drills into the tree A series of pictures showing a Ruby-crowned Kinglet feeding from holes made by a Yellow-bellied Sapsucker The Kinglet and the Sapsucker. This is a commensal relationship when one species benefits (The Ruby-crowned Kinglet) and the other species (The Yellow-bellied Sapsucker) is not affected either positively or negatively.

A Yellow-rumped Warbler is feeding from the holes drilled by a Yellow-bellied Sapsucker in this tree. A variety of animals from insects to birds will feed at these holes. Yellow-rumped Warbler



From Wikipedia: A keystone species is a species that has a disproportionate effect on its environment relative to its abundance, affecting many other organisms in an ecosystem and help in determine the types and numbers of various others species in a community.

Such an organism plays a role in its ecosystem that is analogous to the role of a keystone in an arch. While the keystone feels the least pressure of any of the stones in an arch, the arch still collapses without it. Similarly, an ecosystem may experience a dramatic shift if a keystone species is removed, even though that species was a small part of the ecosystem by measures of biomass or productivity. It has become a very popular concept in conservation biology.


The definition given here is somewhat qualitative in nature because there is not yet an accepted, rigorous definition. At issue is how to measure both abundance and impact and at what point to draw the line. Abundance in this context can be measured by biomass or productivity, among other metrics. Impact is even harder to define. It has been suggested that such keystone predators can be identified in ecosystems by their biomass dominance within ecological functional groups, even though they may be relatively rare in relation to the ecosystem as a whole.

The term is often misused in places where foundation species would be more appropriate. A keystone species is not simply one whose disappearance would alter the ecosystem. Removing any abundant species from any ecosystem will drastically alter that ecosystem by definition. What makes the concept of keystone species attractive to conservationists is that a species with a relatively tiny physical footprint can be critical to the health of its ecosystem.


Kingdom - Formerly the living world was divided up into two kingdoms: animals and plants. Now it is generally recognized that there are five distinct Kingdoms. Prokaryotae (bacteria), Protoctista (nucleated algae, water molds), Fungi, Plants and Animals. (Kingdom, Phylum, Class, Order, Family, Genus, Species)


Kleptoparasite - Stealing food from an individual who has just obtained it. This is especially done by Magnificent Frigatebirds, Bald Eagles, and Parasitic Jaegers.


Learning - From A New Dictionary of Birds (1964) edited by Sir A. Landsborough Thomson and published by the British Ornithologists Union; The learning essay (edited) is by William Homan Thorpe. "Learning is best defined as 'the production of adaptive changes in individual behaviour as a result of experience'. It is contrasted with innate or instinctive behaviour, which does not depend on such individual experience to bring it forth or develop it but is so fully under the control of the hereditary mechanism that it appears at the appropriate time in the individual life cycle irrespective of special experience. There has been considerable difference of opinion as to whether the term 'adaptive' should be included in the definition; the word is used here in order to prevent the term 'learning' from including such changes in behaviour as those resulting from fatigue, sensory adaptation, the effects of injury. This is important, because it is generally agreed that learned behaviour is to be carefully distinguished from changes in behavior caused by physiological or structural damage to the system.

 "Many workers have considered that a more or less frequent repetition of a stimulus or of a changed situation is necessary for learning, but so many examples are now known of learning as a result of a single experience that this contention can no longer be maintained. There are six different categories of learning that are found to be useful in describing behaviour of birds and the higher vertebrates generally, one of which is discussed in a separate article (Imprinting).

"Habituation - This is, in some respects the simplest type of learning found in the Animal Kingdom. It consists of the 'waning of a pre-existing response as a result of repeated stimulation when this is not followed by any kind of reward or punishment' (Reinforcement). It is most evident in nature in relations to avoiding action to more generalized and simple stimuli such as loud sounds, sudden movements, and stimulus or situation that is strange, and any familiar stimulus at an unusually high intensity. Many species of birds, also have the inborn ability to recognise, and immediately take appropriate avoiding action or other response in regard to, certain types of predator, such as hawks and owls, that are particularly dangerous to their species; but such an inherited response to dangers that are of primary significance to the particular species. To have such an instructive response to every kind of predator, and to every and any danger, would be out of the question. Therefore instead of, or in addition to, such specific responses, practically all animals show this ability to become habituated to stimuli that experience shows to be harmless. Obviously, if the response to such stimuli as sudden movements and sounds were completely automatic and unvarying, the life of the animal would become impossible since it would be continually taking cover from the flicker of a leaf and from every passing shadow. Habituation is thus that very simple form of learning which saves an animal from wasting its energies in response to stimuli that experience shows to be of no significance. Habituation is obviously of prime importance in the process of taming birds and other animals, constituting as it does the first step in accepting the abnormal conditions of captivity. The term habituation is used in a general way for any type of response decrement shown by animals; not many examples have been sufficiently fully analysed for us to go further than this. It is, however, now clear that there are at least four types of response decrement included under the general term, and it has become of considerable practical and theoretical importance to distinguish these where possible. They are as follows:

1 - Short-term waning of the response irrespective of the nature of the stimulus - a kind of localized fatigue of short duration (e.g. the waning of the pecking responses of the young Herring Gull after frequent repetition.

2 - Long-term waning of the response irrespective of the nature of the stimulus, e.g. some examples of inhibition of sexual behavior in long-deprived birds. (As yet comparatively little studied.)

3 - Short-term waning of the response to a specific response. This type of behavior may be observed in the changed intensity of the begging response of nestling passerines and may be evidence of some transitory changes in the releasing mechanism, giving rise to a passing lack of attention to the stimulus.

4 - Long-term response-waning specific to the stimulus. This is habituation in the strict sense and, when information warrants it, the term is best reserved for this kind of phenomenon. It is an effect that endures for weeks or months rather than seconds or minutes. Examples specifically studied include the long-term nystagmus (rapid involuntary oscillation of the eyeballs) of both young and adult pigeons (Columba sp.) produced as a result of repeated rotation; similarly, habituation can be shown in the reduction of the number of head movements correlated with the nystagmus habituation to sound signals, which has also been studied in pigeons and domestic chicks.

"Finally, the term 'habituation' is most useful if it is restricted to processes depending on changes in the central nervous system, as distinct from changes in the level of response of the sense organs themselves. This is one of the reasons why it is important to distinguish No.1 type of response from No. 4 above, since the former is much more likely to be due to temporary change in responsiveness of the sense organ concerned.

"Conditioning - In the strict Pavlovian sense this may be defined as 'the process of acquisition by an animal of the capacity to respond to a given stimulus with the reflex reaction appropriate to another stimulus (Reinforcement) when two stimuli are applied concurrently for a number of times.' Conditioning in the strict physiological sense is a most important element in habit formation, but it cannot usually be discriminated from other conditioning factors in the free-living bird. Nevertheless it is of immense importance as being a means by which the releasing mechanism is elaborated or modified to fit the environmental situation more exactly. It consists of the linking of a pre-existing response to a new stimulus without changing the response. Pavlov and his pupils were the pioneers in the laboratory study of the conditioned responses not only of mammals but also of birds; the domestic pigeon has been the species mainly used. Just as with the dog used in salivary conditioning experiments, so the bird has to be trained to stand in a specially devised 'coat' with openings to allow the free movement of the head and one leg only. When this phase of preliminary habituation is completed, the application of a mild electric shock can be used as conditioning stimulus on the presentation of food. A great variety of auditory, visual, tactile, and ampullar stimulations have been successfully used as conditioning stimuli. The conditioning method is of great importance in investigating the range of abilities of the sense organs. The conditioned reflex is not the sole element through which learning is achieved; but, historically, it constituted one of the first ways in which the learning process of animals could be quantitatively and precisely studied in the laboratory, and it remains an invaluable tool for the investigation of the senses of animals.

"Trial-and-error Learning - This is the term used to designate the essential process in the acquisition or specialization of habits. There are many synonyms, such as 'Conditioned reflex type 2', Conditioned reflex type R', 'Instrumental conditioning', 'Thorndykian conditioning', 'Instrumental conditioning' and 'Action conditioning', etc. Of these, perhaps 'Instrumental conditioning' and 'Action conditioning' are the two most appropriate for the phenomena likely to be encountered in the laboratory. Whereas the strict reflex conditioning consists of the linking of a pre-existing response, instrumental conditioning consists of the modification of the response itself or the production of a new response. Thus, whereas classical conditioning is relatively passive, instrumental conditioning involves active motor or appetitive behaviour on the part of the animal. In order to demonstrate instrumental or action conditioning, the generalized appetitive behaviour of the animal is allowed to take place or deliberately invoked (instead of being suppressed, as in the Pavlovian experiment), and this behaviour comprises a number of possible acts. Thus the learning consists in selecting the most appropriate form of these various items of behaviour as a result of the reward that follows them. Strictly, then, reflex conditioning is restricted to the acceptance of a new stimulus, instrumental conditioning to the development of a new act. In fact, the two together make up what could be called trial-and-error learning, which is an expressive name for the behaviour as seen in the normal animal learning in its natural environment. it can now be more precisely defined as 'the development of an association as a result of reinforcement, during appetitive behaviour, between a stimulus or situation and an independent motor action as an item in that behaviour, when both stimulus and motor action precede the reinforcement in time and the motor action is not the inevitable inherited response to the reinforcement'. A particularly good example of trial-and-error learning is the improvement in the co-ordination and control of pecking movements in a bird as the result of experience. Pecking and drinking are based on innate unlearned reflexes and responses, but much of the fine adjustment of both results from trial-and-error learning. Similarly with 'learning to fly'; it has been shown that the essential movements of flight are innately co-ordinated and do not require practice for their development, but once the young bird has taken its first flight it achieves fine adjustments of the flight movements and learns to control alighting and take-off under varying wind conditions as a result of trial-and-error learning. In the same way, trial-and-error learning plays an important part in the improvement of many examples of nest-building; many birds appear to be born equipped with latent nest-building motions, but they have to learn, at any rate to some extent, what materials are appropriate for nest building and how to manipulate them.

"The trial-and-error learning ability of pigeons has been used on a very large scale by Ferster & Skinner (1957) for the fundamental study of the effect of different systems and schedules of reward on learning ability. In this immense study, involving many hundreds of experiments, the pecking response of the pigeon is used as a special instance, the result of which can which can be applied to human learning systems. While the work in itself is in no sense ornithological, it provides a number of results of great interest to the student of the behaviour of birds and other animals. In particular it reveals one of the most important distinctions between classical conditioning and trial-and-error learning. In the former the response has to be rewarded for a high proportion of the occasions on which it occurs if it is to be maintained with its full intensity and efficiency. With instrumental conditioning 'partial reinforcement', that is, the giving of only an occasional reward, may be as effective as, or even more effective than, unfailing reward at every performance. With pigeons under schedules of intermittent reinforcement, Ferster & Skinner describe two birds which were able to respond in a sustained manner when only 1 in every 875 pecks was rewarded by obtaining food. Again, when reward ceases on completion of conditioning, as many as 10,000 pecking responses may appear in the absence of reward before the pecking response has completely subsided. Considering bird behaviour as a whole, trial-and-error learning is infinitely the most important process involved in adjusting voluntary actions to the circumstances of the environment. For it to take place one must first have appetite motivation (e.g. the drive of the pecking response), often governed by curiosity relating to the external environment or some particular part of it.

"It is through trial-and-error learning that play serves its function as a means of acquiring knowledge and skill appropriate to better performance in all the varied activities of the bird's life. It was for long believed that young birds, in contrast with young mammals such as kittens and badger and fox cubs, do not play. This conclusion seems to have been based on insufficient evidence, for there are now so many examples on record of playful behaviour in a great variety of young birds that one must conclude that it is general (See Play). This playful behaviour consists in tilting and sparring matches between young birds, the playful hunting of inanimate objects by young raptors, and the playing with sticks, stones, and other material objects which may be regarded as potential nest material. More elaborate examples of behaviour that can probably be regarded, at any rate provisionally, as play are the soaring and tumbling in rising air currents by Rooks Corvus frugilegus and other birds, and the play of birds such as Eiders and Black Guillemots in torrents and tide races. The most extreme development of what appears to be play is found in the bowerbirds where the bower displays and 'games' seem to have passed far beyond the limits of utilitarianism.

"To sum up, we see that classical conditioning is the establishment of an association between a normal reward or reinforcement (which can usually be regarded as involving a consummatory act) and a new external or exteroceptive stimulus, which is initially indifferent in the sense that it does not innately release any specific responses and so does not have any 'meaning' for the animal. Instrumental conditioning on the other hand, is the establishment of an association between a voluntary major act as part of appetitive behaviour, primarily as perceived by the animal's proprioceptive organs, and the normal reward or reinforcement - the natural reinforcement thus involving a consummatory act or a consummatory situation or both. Thus classical conditioning and instrumental conditioning combine together to make up the full normal process of trial-and-error learning - the first by conditioning the external stimulus to the 'innate releasing mechanism', the second by conditioning a voluntary movement (the motor act) of the appetitive behaviour to the 'innate motor mechanism' of the consummatory act. Thus:


Exteroceptive stimulus + Innate releasing mechanism = Reflex conditioning


Proprioceptive stimulus + Innate motor mechanism = Instrumental (Action) conditioning.


Reflex conditioning + Instrumental conditioning = Trial-and-error learning.

"Both components of learning are regarded as essentially anticipatory in the sense of having prospective reference to an ensuing reinforcement in the form of a reward or a consummatory act, but whereas the first component is essentially passive, the second involves active trial - or appetitive behaviour.

"Latent Learning - In the types of learning so far described the performance is established or stereotyped as a result of the attainment of some kind of reward, e.g. food, drink, effective nest building, or control of flight movements. It has long been recognized that in some animals another type of learning can be discerned which is independent of reward in the ordinary physiological sense of the term. The classical experiment is as follows: a litter of young rats is divided into two groups, one of which is placed for a period every day for ten days in a particular maze of a particular pattern and allowed to explore this maze at random; the others are given no such experience. If, then, both groups of rats are given identical training in such a maze by being rewarded in the normal manner by finding food in the food box on completion of the run, it will be found that those rats which had had the chance to explore the maze previously (but without being rewarded for it) had, in fact, learnt a great deal about its layout and show a striking decrease both in errors and time of running as compared with the control group. A simple maze may in this way be entirely mastered through random exploration, but this learning is latent in that it cannot be demonstrated until the introduction of a reward. Latent learning can thus be defined as 'the association of indifferent stimuli or situations (i.e. situations without reward)'. One cannot conveniently train pigeons in mazes, but there is little doubt that latent learning is a laboratory version of what is a very general feature of animals that in nature have to find their way about. There is no doubt that a great deal of the learning displayed by birds in getting to know territory, individual habitat, migration routes, and so on, resembles latent learning in that the learning achieved is not immediately rewarded in the ordinary physiological sense. Also, like latent learning, it implies a tendency to explore the environment and to learn as a result the characteristic features and their special relations to one another.

"Insight and Insight Learning - The term 'intelligence' has no precise connotation for students of animal behavior and is best avoided. Its place is taken by the term 'insight learning' which is defined as 'sudden adaptive re-organization of experience' or 'the sudden production of a new adaptive response not arrived at by overt trial-and-error behaviour'. In mammals the precise evidence for insight is provided chiefly by the ability to learn a special kind of maze or detour problem such that when the animal has learnt one roundabout way through a maze it is able to 'see' that there is another shorter way that can be taken, and can show its insight into the maze situation by taking this short cut as soon as it is allowed to do so, without having actually traversed the path before. The sudden production of a completely new response such as is shown by the tool-using behaviour of the higher mammals also comes under this category. With birds the existence of insight and learning of this fully developed kind is difficult to establish, although there are many observations suggesting that it may also occur. Evidence for insight can, however, also be obtained from experiments in which the animals shows evidence of ideation. Ideation may be defined as the occurrence of perceptions, in the absence of the corresponding external stimulus, in the form of images that are in some degree abstract or generalised and that can be the subject of further 'mental' comparison and reorganisation by learning processes. Such promising lines of investigation such as those which have led to the demonstration of the phenomenon of 'reminiscence' in rats, have not yet been attempted with birds. With birds the ability to deal with a number and to abstract a numerical quantity from a given number of specific objects provides perhaps the best evidence available for ideational process."

LeConte, John - (1818 - 1891) Trained as a medical doctor, Le Conte studied mostly insects. The LeConte's Thrasher was named after him and the LeConte's Sparrow was named after his cousin, John LeConte.


Life zones - A system originated from C. H. Merriam in the late nineteenth century to correlate distribution of plants and animals to zones determined by temperature. West coast zones would be Arctic, Hudsonian, Canadian, Transition, Upper Sonoran and Lower Sonoran. This system is not currently used since distribution of plants and animals is influenced by more than just temperature.


Mast - (from Wikipedia) The edible seed and fruit produced by trees or shrubs that wildlife species will consume


Mayr, Ernst - (1904 - 2005) (From Wikipedia) "Ernst Walter Mayr (July 5, 1904, Kempten, Germany – February 3, 2005, Bedford, Massachusetts U.S.), was one of the 20th century's leading evolutionary biologists. He was at the same time a naturalist, an explorer, an ornithologist and science historian. His work contributed to the conceptual revolution that led to the modern evolutionary synthesis of Mendelian genetics and Darwinian evolution, and to the development of the biological species concept. Neither Darwin nor anyone else in his time knew the answer to the 'species problem': how could different species evolve from one common ancestor. Ernst Mayr approached the problem with a new definition for the concept 'species'. In his book 'Systematics and the Origin of Species' (1942) he wrote that a species is not a group of morphologically similar individuals, but a group that can breed only among themselves, excluding all others. When groups of identical individuals get isolated, the sub-populations will start to differ by genetic drift and natural selection over a period of time, and thereby evolve into new species. His theory of peripatric speciation (a more precise term for the subset of allopatric speciation he supported) based on his work on birds is considered as one typical mode of speciation, and is the basis of the theory of punctuated equilibrium. Apart from biological subjects, his prolific writings include works on the philosophy and history of science in general, and of biology in particular." He is author of Birds of the Southwest Pacific. Some of his writing can be viewed in the natural history accounts of these species: Red-winged Blackbird,


Melanism- Dark color that is the result of a large quantity of the pigment melanin. In many hawk species there are individual birds that are darker than the majority of the species. These are quite often known as dark morphs. Some authorities maintain that flight feathers last longer when they have melanin such as White Pelicans who have black feathers on the edges of their wings.


Merriam, C. H. - (1855 -1942) - One of the founders of the American Ornithologists' Union (AOU), Merriam was a zoologist who worked for the Biological Survey in Washington, D.C. during the late nineteenth century. He developed the concept of life zones. He had one of the sub-species of the Wild Turkey named after him. See also Natural History of Green-tailed Towhee and Lazuli Bunting. His sister was Florence Merriam Bailey.

From Wikipidea : Clinton Hart Merriam (December 5, 1855-March 19, 1942) was an American zoologist, ornithologist, and ethnographer. He was born in New York City in 1855. His father, Clinton Levi Merriam, was a U.S. congressman. He studied biology and anatomy at Yale University and went on to obtain an M.D. from the School of Physicians and Surgeons at Columbia University in 1879. In 1886, he became the first chief of the Division of Economic Ornithology and Mammalogy of the United States Department of Agriculture, predecessor to the National Wildlife Research Center and the United States Fish and Wildlife Service. He was one of the original founders of the National Geographic Society in 1888. He developed the "life zones" concept to classify biomes found in North America. In 1899, he helped railroad magnate E. H. Harriman to organize an exploratory voyage along the Alaska coastline. Some species of animals that bear his name are Merriam's Wild Turkey (Meliagris gallopavo meriami), the now extinct Merriam's Elk (Cervus elaphus merriami), and Merriam's Chipmunk (Tamias merriami). Much of his detail-oriented taxonomy continues to be influential within Mammalogical and Ornintholical scientific circles. Later in life, funded by the Harriman family, Merriam's focus shifted to studying and assisting the Native American tribes in the western United States. His contributions on the myths of central California and on ethnogeography were particularly noteworthy. His sister Florence Augusta Merriam Bailey was a pioneering ornithologist who introduced the idea of popular field guides for bird identification. He died in Berkeley, California in 1942.


Mesic - A moderately moist habitat; as opposed to a xeric habitat which is dry.

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Migration - The movement of various organisms from one area to another. Some migrations are very modest as a species will go from an area where it is convenient to breed, to an area where it is easier to spend the winter. Other migrations are more dramatic as small songbirds, such as the Black and White Warbler, fly from Canada, where they breed, to South America where they will spend the winter. An excellent source on migration is Scott Weidensaul's book, Living on the Wind.


 Millinery trade - The practice of adorning hats with the feathers of birds. The courtship feathers of the Great Egret were highly valued and much prized. Many birds were killed to satisfy the business and of course the birds were killed during the breeding season so the loss of birds was very dramatic. This practice almost caused the extinction of the Great Egret and was partially responsible for the establishment of the Audubon Society, to protect birds.

Mollusks - Invertebrates of the phylum Mollusca. Examples include clams, oysters, snails, squid, slugs, octopus. Number of species is currently estimated to be about 50,000.


Molt - The periodic shedding and replacement of feathers. Different species have different methods of molting. (Long-tailed Duck) From, The Birdwatcher's Companion : "The process by which a bird renews a part or all of its plumage, including the growth of new feathers (endysis) as well as the loss of the old (ecdysis). Sometimes, confusingly, 'molt' is used to mean the sheding process only. Other types of plumage changes - such as those caused by feather wear - and the shedding of parts other than feathers are sometimes encompassed in a looser defintion of the term.

"A bird's plumage is crucial to its survival. Its specific functions vary greatly from one type of bird to another, but for most it serves at least as insulation, protection, transportation, and identify. Plumage also wears out by normal fiction (abrasion), is eaten by a variety of live-in pests (ectoparasite), and is vulternable to accidental damage. These facts of birdlife explain the need for periodic molting.


Morph - Some species of birds come in various colors. The Snow Goose has two color variations - the more prolific white color and the blue color, sometimes called the Blue Goose. The Blue Goose used to be considered a distinct species until it was realized that it was instead a variation on the more common white color. At the same time it has been believed that the Screech Owl had various color phases before it was realized that there were indeed two distinct species of Screech Owls. The Reddish Egret has a red morph and a white morph, which is not to be confused with the Little Blue Heron which as an immature bird has a white plumage. The Northern Fulmar has a variety of color variations that go from very white to very dark. Many hawks, including the Rough-legged, Ferruginous, Red-tailed, Swainson's, and Harlan's, have both a light morph and a dark morph. Previously the word phase was used to denote a morph, but a morph does not become lighter with age. Phase implies that the bird will grow out of its color eventually. Also referred to as polymorphism. From A New Dictionary of Birds: "Term denoting the co-existence in a single interbreeding population of two (dimorphism) or more readily distinguishable and genetically determined forms - called 'morphs' ('phases in older terminology) - all in numbers too great to be due merely to recurrent mutation. Familiar avian examples are the egg polymorphism of the various cuckoos (Cuculidae), the white and blue plumage dimorphism of the Reef Heron, and the numerous cases described as 'mutations' by Stresemann."

From The Birdwatcher's Companion : "A 'morph' is a variation (form or 'phase') that may occur within a population of a given species (as distinct from racial variations) e.g., the 'dark morph' of the Pomarine Jaeger or the 'ringed phase' of the Common Murre."


Morphology - The study of the form and shape of an animal.


Muir, John - (1838 - 1914) - From Wikipedia: "(April 21, 1838 – December 24, 1914) was one of the earliest, and perhaps the most important of, modern conservationists. His letters, essays, and books telling of his adventures in nature, especially in the Sierra Nevada Mountains of California, were read by millions and are still popular today. His direct activism helped to save the Yosemite Valley and other wilderness areas. The Sierra Club, which he founded, is now one of the most important environmental organizations in the United States. But more than that his vision of nature's value for its own sake and for its spiritual, not just practical, benefits to mankind helped to change the way we look at the natural world." Some of his writings may be viewed at Dipper,


Naming Birds - We generally give birds two names: the Common Name and the Scientific Name. The Common Name is the one generally used by the public and the Scientific Name is used by ornithologists and serious birdwatchers. The advantage of the scientific name is that when you refer to the Red-tailed Hawk as Buteo jamaicensis, an ornithologist who speaks a different language and doesn't know what the name Red-tailed Hawk refers to, will know the identification marks of the genus Buteo.

The process of naming birds has its share of difficulties. The House Sparrow is a good example of the difficulty of a name. It used to be called the English Sparrow, but it is not English and it is not a sparrow. It is really originally from Africa and was considered related to a family of birds called weaver finches (Ploceidae) but now (2006) is included in the family Passeridae. For a good discussion on the House Sparrow. The European Blackbird (Turdus merula) is not really a blackbird, but is instead a thrush; it is related to the American Robin (Turdus migratorius). The common name is Blackbird, but its scientific classification is as a thrush. It shares the same genus as the American Robin.

European Blackbird
The European Blackbird (Turdus merula) (pictured on the left) is not really a blackbird, but is instead a thrush. This bird was photographed in Luxumberg Gardens, Paris, France.



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Nest - Place that birds use to incubate their eggs. Some species also use the nest to raise their young until they fledge. There are as many different types of nests as there are species of birds. Some nests are very basic while others are quite complex. Some are very small (Hummingbird) while others grow larger and larger over the years (Osprey). Many shorebirds create little scrapes on the ground to protect their eggs but once the young are born the scrape is abandoned since the young are precocial. The nests for altricial young have to provide more protection for a longer period of time.


Nice, Margaret - (1883 - 1974) - American ornithologist who developed the science of studying a particular species in the field to create a complete natural history and authored over 60 articles on the study of birds. She published her study of the Song Sparrow , titled Studies in the Life History of the Song Sparrow. Link "Margaret Morse Nice was one of the world's foremost ornithologists. Almost entirely self-educated, working without an academic position or access to research funds. Nice, in the words of noted ornithologists Ernst Mayr, 'almost single-handedly initiated a new era in American ornithology ... She early recognized the importance of a study of bird individuals because this is the only method to get reliable life history data.' Margaret Nice achieved this prominence while raising five daughters on the modest earnings of her husband, Leonard Blaine Nice, a professor of physiology. Her achievements can be viewed as, among other things, an extraordinary triumph of the will." From Birdwatching with American Women by Deborah Strom, published by Norton, 1986. Some of her writing can be viewed in the natural history accounts of these species: Scissor-tailed Flycatcher , Tufted Titmouse, Song Sparrow.


Niche - Primarily refers to the role an organism plays within its community (habitat). "The ecological role of a species in a community; a multidimensional space to which that species is restricted by the presence of competitive species or life history requirements." Introduction to California Birdlife, Jules Evens and Ian Tait; California Press, 2005.


Nictitating membrane - A third eyelid that helps to protect the eye. From A New Dictionary of Birds: "Like many other vertebrates, birds have a nictitating membrane or third lid which lies under the lids on the nasal side and can be drawn horizontally across the eye. In diurnal birds this is usually transparent and can be drawn across the cornea to clean or moisten it without shutting out the light." Visible in this Fish Crow and Swainson's Hawk.


Nidifugous - young birds that leave the nest immediately or soon after hatching; see precocial


Nuttall, Thomas - (1786 - 1859) American ornithologist who created one of the first "field guide" to American birds, A Manual of the Ornithology of the United States and Canada. He discovered the Tri-colored Blackbird in California in 1836. The Nuttall's Woodpecker, and the scientific name of the Yellow-billed Magpie (Pica nuttalli) and the Common Poorwill (Phalaenoptilus nuttalii) were named after Thomas Nuttall. Some of his writing can be viewed in the natural history accounts of these species: Whooping Crane, Tri-colored Blackbird,


Obligate - A species that is dependent on a very narrow food base. The White-tailed Kite feeds almost entirely on mice of the genus Microtus. The kite has been described as a Microtene Obligate. The Snail Kite feeds entirely on snails, and specifically the Apple Snail (Pomacea paludosa).


Oologist - one who participates in oology, the study and collection of eggs.  


Opportunistic - Term used to define the feeding habits of organisms that will take whatever food is available. Species, like Starlings, Brewer's Blackbirds, Common Crows, and most of the jays, are opportunistic feeders.


Order - The level of classification between Class and Family. Depending on which authority you use there are 23 Orders of birds in the world and 19 orders of birds found in the United States. This number could change in the next few years, if Flamingos are put back into their own order. Some accounts have combined more species into the order Ciconiformes (2006) which will result in fewer Orders of birds. (Kingdom, Phylum, Class, Order, Family, Species)

albatrosses, shearwaters, petrels
pelicans, frigatebirds, tropicbirds, booby
long-legged wading birds (herons, egrets, bitterns, etc.)
cranes, rails, coot, limpkin, vultures
swans, geese, and ducks
grouse, quail
hawks, eagles, etc.
pigeons, doves
shorebirds, gulls and terns, jaegers, alcidaes (puffins, murres, auklets)
cuckoos, roadrunner, ani
hummingbirds, swifts

Ornithology - The scientific study of birds. It is a branch of zoology, which is the study of animals. Ornithology utilizes both laboratory study and field study to find out how birds operate physiologically, to understand their behavior, how they relate to their environment and other animals (ecology), and which species is related to which other species (speciation). Beyond Birding


Parasitic - Taking resources from another individual to the detriment of that individual. There are many examples of parasitic behavior amongst birds. The behavior of the Brown-headed Cowbird is an example of a type of parasitism. Kleptoparasitism is another example. There are many types of parasites that live off of birds.


Pelagic - Refers to animals that spend the majority of their time in the open ocean. Examples of pelagic birds include the Black-footed Albatross, and the Sooty Shearwater, etc. The Pelagic Cormorant, despite its name, is not a pelagic bird because it spends most of its nights on land. It only uses the immediate coastal waters.


Peterson, Roger Tory - (1908 - 1996) American ornithologist and artist who revolutionized the process of identifying birds thus making the science of birdwatching available to the public through his field guides.


Phylum - The next order of classification after Kingdom. Birds belong to the phylum, Vertebrates. (Kingdom, Phylum, Class, Order, Family, Genus, Species)

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Pigment - Pigments are responsible for the color that we see in feathers, beaks, and legs. Albinism is the absence of pigments.


Play - From A New Dictionary of Birds (1964) - "a form of activity much less apparent in birds than in many mammals, but nevertheless occurring - and not exclusively in the young. Playful behaviour in young animals can commonly be identified as, so to speak, a 'rehearsal' of adult activities; so it forms a part of the learning process, whereby innate capabilities are educated for full performance. Thus, nestling birds will often, in the absence of other rmotivation, engage in sparring matches with each other; or, in the case of raptors, will make hunting movements towards inedible objects; or will manipulate potential nest material. Young Christmas Island Frigatebirds Fregata minor minor, already on the wing, have been seen to swoop at, pick up, and then drop, leaves and other objects floating on the surface of the sea.

"Seemingly playful actions of adult birds, of which a few examples are known, cannot be so readily explained. Rooks Corvus frugilegus will commonly indulge in tumbling aerobatics; and Ravens C. corax have been described as, in addition, carrying up twigs or pieces of heather, which they drop and then catch again in the air. Various aquatic birds, e.g. Eider Someteria mollissima and Black Guillemot Cepphus grylle, have been seen to disport themselves in swift currents in a way that appears to serve no useful purpose, and that to the human mind suggests merely 'having fun'. Similarly, Adelie Penquins Pygoscelis adeliae have been described as riding in vociferous parties on small ice-floes in a tide race, only to swim back to the starting point and begin again.

"However amusing some of the antics may appear to the human eye, one has to be careful to exclude from consideration, in this regard, all forms of display they serve social, sexual, or self-perserving ends. Nevertheless, one is tempted to think that some of the performances of bowerbirds may go beyond such needs."


Plumage - The collective term for the feathers that cover a bird's body. There are many variations on the type of plumage a bird has. In some gulls it takes three to four years for particular species to reach adult plumage and they have a unique plumage for each of those years (California Gull, Western Gull). In other species there is strong difference between male and female plumage (Red-winged Blackbird), and in other species there is strong difference between winter and spring plumage (Horned Grebe). In some species there is a dramatic difference between immature and adult plumage (Yellow-bellied Sapsucker). Sometimes you can see a bird that is "in between plumages" as the immature male Rose-breasted Grosbeak. Many species keep the same plumage all year long (Rufous Hummingbird) but change the feathers during their molt. Some species have variation within the species which results in very different plumages (Reddish Egret, Northern Fulmar). As with all organisms there is always the chance of having plumage that doesn't have any pigment, producing an albino individual (Red-tailed Hawk). Most species' common names refer to their spring male, plumage. The Black-bellied Plover does have a black belly in the spring but in the fall is very gray and undistinguished. The Cinnamon Teal does not change plumage during the year but only the male has a cinnamon color. The female is brown. The plumage of a bird is maintained through their care behavior.


Polygynous - Having more than one female as a mate at one time


Population - Generally refers to the numbers of a species within a particular area. "The total number of individuals in a given area. The term can be used to describe all of the individuals which occupy a particular plot of habitat at a particular time, e.g., the breeding-bird population of a specific pine-oak woodland; or to refer to all the living members of a species, e.g., the world population of Brown Creepers." From The Birdwatcher's Companion. When talking about the White-crowned Sparrow it is important to keep in mind the different races that make up the species. Within the Bay Area of California there are races of the White-crowned Sparrow that migrate to breed and there are races that stay in the Bay Area to breed.

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Precocial - Baby birds that are born with the ability to, within some number of hours, move on their own and feed themselves. Most shorebirds and grouse/quail are precocial young. While there are many variations of both altricial and precocial, in general precocial young leave the nest when they are born and altricial young stay in the nest and are fed and kept warm by their parents. See Young Birds.


Common Loon preening Great Egret preening Great Blue Heron Preening  


Predator Prey Relationship - The relationship that exists between the predator and the animals that it feeds upon. This can be understood in the Inuit tale, The Wolf and the Caribou, paraphrased by Farley Mowat in his book, Never Cry Wolf.

"In the beginning there was a Woman and a Man and nothing else walked or swam or flew in the world until one day the Woman dug a great hole in the ground and began fishing in it. One by one she pulled out all the animals, and the last one she pulled out of the hole was the caribou. Then Kaila, who is the God of the Sky, told the woman the caribou was the greatest gift of all, for the caribou would be the sustenance of man.

"The Woman set the caribou free and ordered it to go out over the land and multiply, and the caribou did as the Woman said; and in time the land was filled with caribou, so the sons of the Woman hunted well, and they were fed and clothed and had good skin tents to live in, all from the caribou.

"The sons of the Woman hunted only the big, fat caribou, for they had no wish to kill the weak and the small and the sick, since these were no good to eat nor were their skins much good. And, after a time, it happened that the sick and the weak came to outnumber the fat and the strong, and when the sons saw this they were dismayed and they complained to the Woman.

"Then the Woman made magic and spoke to Kaila and said: 'Your work is no good, for the caribou grow weak and sick, and if we eat them we must grow weak and sick also.'

"Kaila heard, and he said 'My work is good. I shall tell Amorak [the spirit of the wolf], and he shall tell his children, and they will eat the sick and the weak and the small caribou, so that the land will be left for the fat and the good ones.

"And this is what happened, and this is why the caribou and the wolf are one; for the caribou feeds the wolf, but it is the wolf who keeps the caribou strong."

For a long time wildlife management procedures in the United States worked from the understanding that the predators were enemies of the prey. In order to maintain a strong and numerous deer population it was necessary to get rid of the predators such as the wolf and coyote. Eventually management adopted the ecological approach and understood that the predator had a beneficial effect on the prey. Without the presence of the predator the prey's population numbers could get to a point that the population could not be fed by food available.


Preening - The process that birds use to keep their feathers in order; to maintain the protection that the feathers provide for the bird.

Race - Variations within a species; also referred to as sub-species. Sometimes with more study a race is recognized to be a distinct species which is what happened with the Western Grebe and Clark's Grebe. Two species can also be lumped together when it is realized that they are races of the same species (Northern Flicker). The Northern Flicker previously was split and we recognized the Red-shafted Flicker and the Yellow-shafted Flicker as two different species.


Range - Range defines where a species is found. Range includes both breeding and wintering areas. Some species occupy different habitats during their breeding time than they do during wintering period.


Raptors - Term used to refer to hawks and owls and refers to their ability to catch other animals. It is, in many ways, a misapplied term since many other birds prey on a variety of animals. All the long-legged wading birds (Gt. Blue Heron, Gt. Egret, etc.) feed on a wide variety of vertebrates and invertebrates. Flycatchers prey on insects as do swallows and many others. The Kestrel feeds primarily on insects.


Rhynchokinesis - The ability of the tip of the bill of many shorebirds to be very pliable as seen in this Short-billed Dowitcher.

From The Game Birds of California (1918) "Much of the food of the snipe is secured by probing in soft mud, a practice to which its bill is particularly adapted. The tip of the upper mandible is flexible and can be moved independently of the lower one, and the exposed surface toward the tips of both mandibles is provided with numerous sensitive nerve-endings, each in a little pit. The birds are thus enabled to feel about with the tip of the bill below the suface, a practice not possible for any other wader except the Woodcock of the east and probably the Dowitchers. The bill is thrust perpendicularly into the soft mud and worked about for earthworms and other burrowing forms of animal life without the incessantly repeated probling neccessary for waders provided with shorter, more unflexible, and less sensitive bills;"

From Waders, W.G. Hale, 1980. "In most waders the distal part of the upper mandible is not only pliable but capable of being raised and lowered independently of the rest of the bill, so that only the tip of the bill may be open, or the tips of the two mandibles might be touching whilst there is an open gap in the middle. This property is known as rhynchokinesis and is moderately developed in some waders such as the Plovers and highly developed in the Curlews and Snipes."

Ridgway, Robert - (1850 - 1929) American ornithologist


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Scavenger - An animal that eats available food such as garbage, and carrion. Examples include the Black-footed Albatross, the Turkey Vulture, and smaller birds such as the Common Crow, the magpies, and others. Some species will change from their usual food gathering role and become scavengers when the opportunity presents itself. I once watched a Gt. Egret eat parts of fish left from human fisherman that were cleaning their catch.


Scientific Method - The process of establishing an hypothesis and gathering data that either proves or disproves the hypothesis. Scientific method is discussed in Beyond Birding.


Scrape - The most basic form of a nest, the scrape is a small depression in the ground where the eggs are laid. This is usually done by shorebirds including plovers, Black Skimmer, and the Least Tern.


Sexual Dimorphism - When the female and the male of a species have different plumages. The differences in the plumage can range from entirely different as in the Northern Harrier, or more subtle as in the Acorn Woodpecker.


Shorebirds - A term that is vague in its usefulness. It generally refers to birds that are found along the edge of water. This term is used to refer to members of the order Charadriformes which includes members of the families, plovers, sandpipers, phalaropes, oystercatchers, etc. But many shorebirds that spend their non-breeding time around water, will migrate and spend their breeding time in a very different habitat.


Skutch, Alexander - (1904 - 2004) - Contemporary ornithologist who lived in Costa Rica for over 60 years. He studied the birds of Central and South America and wrote many books about particular families of birds such as flycatchers, antbirds, tanagers, hummingbirds, and woodpeckers. One of his most famous books is Parent Birds and their Young. He was born in 1904 and died in 2004. Some of his writing can be viewed in the natural history accounts of these species: Groove-billed Ani, Green Kingfisher, American Goldfinch, Purple Finch, Wilson's Warbler, Tennessee Warbler, Summer Tanager,

(From Wikipedia) Doctor Alexander Frank Skutch (1904 – 2004) was a naturalist writer. He published countless scientific papers and books about birds, which were his passion. He also wrote several books on philosophy. Alexander Skutch was born on May 20, 1904 in Baltimore, Maryland. He received a Doctorate in Botany from Johns Hopkins University. He then traveled to Panama and Honduras, where he studied bananas. During this time he acquired a deep interest in birds and began studying their habits. Skutch collected plants to make money, but observing birds remained his life’s main focus. In 1941, he purchased a farm in Costa Rica, where he lived for the rest of his life. In 1950, Skutch married Pamela Lancaster, who was also a naturalist. Alexander Skutch died on May 12, 2004, one week before his 100th birthday.


Social - The inclination of a species to operate as a group. Some species are very individual and some are very social. Most shorebirds are very social (Western Sandpiper, Dunlin). They feed, roost, breed as a large group. Other shorebirds such as the Wandering Tattler feeds by itself. Other birds feed by themselves (Gt. Egret) but sometimes feed as a group. The Gr. Egret, while it may feed on its own, generally nests in colonies which provide each individual the benefit of protection by the others.


Song - Includes all sounds made by birds including those that are made by their bill, their feathers, etc. Birds use their syrinx to make sounds while humans use their larynx.


Speciation - The process by which new species are evolved. Some of the confusion with this term can be seen in the natural history account of the Bank Swallow, and also the McCown's Longspur.

From The Birdwatcher's Companion "The process by which new life forms evolve from those already in existence.

"All plants and animals - including birds and humans - have always been and continue to be, ever-changing.

"The 'opportunity' to change is offered by the regular occurrence of random gene mutation which is controlled, according to its survival value (or lack of it), by natural selection. In a small unified population of a species any advantageous mutation which arises in an individual tends to be acquired in time through interbreeding by the whole population. In this case, the species in question changes in character but it remains a single entity made up of like individuals. However, if two or more populations of a species become separated from one another, the characteristics of each begin in their own unique ways, and because the isolated populations can no longer interbreed, the new mutations cannot be shared. Differences between separate populations first begin to appear as barely discernible tendencies, e.g., a greater number of slightly paler, longer-billed individuals in one population than in another. If the tendencies continue in opposite directions, the populations become readily recognizable races or subspecies - one long-billed and pale, the other short-billed and dark - but would still interbreed freely and successfully if the populations were reunited. As the populations continue to 'grow apart,' however, their willingness and ability to interbreed continue to decline, and when the sharing of genetic traits become impossible (or at least highly unlikely), the populations have evolved into distinct species. Though this process is called speciation, it begins, as we see, with individual variation and does not stop with the evolution of a new species. Each new species has the potential for continued divergence, and since there are few limitations on the degree of change possible, the process can continue up the phylogenetic ladder. The same 'system' which produced that slightly paler, longer-billed individual was also responsible, as it were, for making birds from reptiles.

"Needless to say, speciation takes time. Archaeopteryx did not go to bed a reptile and wake up a bird. The traditional view of biological change (evolution) is that it takes place very gradually over eons, but many modern theorists now believe that it may occur in (relatively) quick adaptive bursts, interspersed with long periods during which the organism in question remains genetically static. Of course, fundamental and complex changes, e.g., skeletal modifications or the transformation of scales into feathers, are still long-term processes. But relatively superficial, yet conspicuous changes in color and size can be noticed within a few decades. House Sparrows, for example, which were first introduced into North America around 1850, have already evolved distinctive forms in response to ecological influences so universal in their effect on bird morphology that zoologists have names for them.

"How Populations Become Isolated. The separation of animal populations can result from sudden cataclysms, gradual, relatively confined processes, or anything in between. A few minor and frequent phenomena should be mentioned:

"Continental Drift separated populations of hundreds of thousands of organisms, giving rise to what are now the highly distinctive faunas of South America, Africa, Australia, etc.

"Glacial Advances moving southward across the landmasses of the Northern Hemisphere split continents and habitats into eastern and western regions. It is theorized, for example, that a great coniferous forest once transcontinental in North America was divided during one of the Pleistocene advances, allowing bird and other faunas to plot separate genetic courses. This explains in part why it is now practical to have eastern and western field guides.

"Mountaintop Islands of habitat into which populations retreat and begin to change can result from glacial invasion or geological events such as uplift and vulcanism. The races (or species?) of rosy finches isolated in different parts of the Rookies exemplify this kind of genetic isolation in North America. Some high mountains in the tropics have evolved their own unique avifaunas by this process.

"Oceanic Islands can also be hotbeds of speciation witness the many species which are unique to one or a small group of islands in the West Indies or Polynesia. Most of these island 'endemics' are probably descendants of storm-driven vagrants from mainland populations. Some (e.g., Darwin's famous finches of the Galapagos Islands and many forms on Madagascar) have evolved with such abandon for so long that they no longer have any close off-island relatives. The Bermuda race of the White-eyed Vireo, on the other hand, has just begun its evolutionary divergence from the other members of its species. In the relatively recent past, a population of White-eyes established a resident population on Bermuda. The so-called Chick-of-the-Village never leaves the islands, and mainland White-eyes passing through in the fall never remain to breed. At present the Bermuda birds are distinguished from other races only by such inconspicuous differences as shorter wings, but over time its physiology and/or behavior will likely become so changed as to render it unable or unwilling to mate with any form of White-eyed Vireo. It will have evolved from Vireo grisus bermudianus (the Bermuda White-eyed Vireo) to Vireo bermudianus (the Bermuda Vireo).

"Distance. Species with very broad ranges may evolve in different directions toward the extremities of their range, even though they remain genetically linked. Changes in color or size, for example, tend to be graduated geographically between poles in such cases, so that it is often impossible to draw sharp boundaries between the end of one race's range and the beginning of another's (cline). In rare instances the diverging range of such a species is circular, with the extremities meeting, and the races being sexually incompatible (ring species). This makes a quandary for the taxonomist who must decide whether he is dealing with one species or two, and if the latter, how to define their breeding ranges. The Song Sparrow may be the champion North American 'diverger,' with about 30 recognized races within its unified range; interestingly, other species almost equally widespread change little over their range.

Respecting Barriers. The factors which separate populations, thus encouraging speciation, need not be vast oceans or thousands of miles of glacial ice. Particularly in tropical regions, the barriers between populations of different races of birds may be no more formidable than a river or narrow strait. Ecological barriers such as an intervening 'wall' of forest between two deserts (or vice versa) often remain unbroached even though the width of the barrier is negligible. However, such barriers are not equally respected by all forms. Some yield to the isolating forces and become distinct, while others interact with the wider 'gene pool' beyond and retain their species' homogeneity.

"The Ways of Changing. Given the different scenarios which can produce genetic isolation and the adaptive cunning of mutation/selection, it is not surprising that speciation progresses in a number of different ways.

"To begin with, there seems to be some biological formulas which govern animal form and coloration according to differences in climate. For example, populations of bird species tend to be smaller and paler in hot, dry regions than their counterparts in cool, humid regions. The validity of these generalizations is much more apparent in a tray of museum specimens from different climates than in the field, and there are numerous exceptions, but there is no doubt that they play a role in speciation.

 "A more 'inventive' force for change is called adaptive radiation, the tendency of animals to diversify in accordance with the available ecological niches. If we placed a population of robins on a birdless island with a variety of habitats, and returned after a few million years, we might find no sign of the bird that pulls worms from our lawn. We might, however, find a species of robin with a long tail which caught flying insects from a treetop perch, another which lived deep in the forest and fed only on fruit, a third with longer bill and legs which waded in shallow water and caught fish, etc. These fanciful robins are not so different, in fact, from the Drepanididae, a family (honeycreepers) which apparently evolved in isolation in the Hawaiian Islands in just this way.

"As species evolve in different ways away from their common ancestors, the adaptations they acquire to suit a particular life style may make them look strikingly different from other species to which they are really closely related. This is called adaptive divergence and is well illustrated among the members of the American blackbird family (Icteridae): the Bobolink has developed the appearance and habitat and food preferences common to many finches; orioles, on the other hand, are more like tanagers or warblers in these respects; the meadowlarks, also icterids, resemble neither the Bobolink nor the orioles, but look and act a great deal like some African species in the pipit family called longclaws. This chance development of similar characteristics in families of birds only distantly related is called adaptive convergence."

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Species - The term species refers to the smallest classification level. Generally this term is used to refer to a specific member of a family of birds. When we talk about woodpeckers, we are not talking about the species level. When we talk about the Acorn Woodpecker we are talking about a specific species. The concept of the species is difficult to precisely define as our knowledge of the concept keeps changing as we improve our understanding of DNA. Also our understanding of the biology of bird song is teaching us more about the concept of speciation. The difficulty of the term also becomes obvious as we look at name changes that have occurred over the past 50 years. The Oregon Junco and the Slate-colored Junco are now considered one species - the Dark eyed Junco. Instead of being two distinct species they are now understood to be subspecies. Our understanding of the concept of species is very connected to our understanding of the terms hybrid and cline. (Kingdom, Phylum, Class, Order, Family, Genus, Species)

 Spiders - Sometimes feed on small birds captured in their webs. A list, recently gathered, of birds found in spider webs included the Anna's Hummingbird, Costa's Hummingbird, Ruby-throated Hummingbird, Yellow-bellied Flycatcher, Acadian Flycatcher, White-eyed Vireo (fledgling), Swainson's Thrush, House Wren, Bushtits, House Finch, Lesser Goldfinch, American Goldfinch, Grasshopper Sparrow, Yellow Warbler, Yellow-throated Warbler, Common Yellowthroat, and the American Redstart.


Split - The Western Grebe was split into two species, the Western Grebe and the Clark's Grebe. This determination is based on a variety of factors (plumage, voice, distribution, etc.) but now is primarily based on DNA analysis.


Sub-species - A population within a species that can be distinguished from other members of that species; sometimes referred to as a race. Within the White-crowned Sparrow there are at least five sub-species that have been distinguished.. For further discussions refer to the text in Bent under the Speciation Themes, see especially the natural history notes for Song Sparrow. Sometimes sub-species can be recognized as actually being a different species. When this occurs a species is split (see next definition). See also Bank Swallow . From A New Dictionary of Birds: "a population of which the members can be morphologically distinguished, if sometimes only on average, from the members of other populations of the species to which all belong; the term 'race', or 'geographic race', is used synonymously and is in some ways a truer representation of the concept. In Mayr's words, subspecies are 'geographically defined aggregates of local populations which differ taxonomically from other such subdivisions of a species'."


Sunning - A type of care behavior. Birds will sit in the sun and move the feather tracts of their body around so the warmth of the sun can get to the rest of their body. Steller's Jay, Roadrunner, Robin, Gt. Blue Heron, Mourning Dove


Superspecies - Species that are very closely related. For example, the Western and Eastern Meadowlarks, the Oak Titmouse and Tufted Titmouse and many other species. These species used to be the same species and then diverged, probably due to geographic isolation. For a list of possible super species in the US.


Sutton, George M., - (1898 - 1982) American ornithologist; Professor Emeritus at the University of Oklahoma and author of At a Bend in a Mexican River and others.


Sympatric - Closely related species or subspecies, whose geographic ranges overlap as contrasted with allopatric.


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Taxonomy - The study of classification.


Territory - The physical area that a bird defends. Generally this is an area that they defend so they are able to acquire a mate and obtain food for their young. I have also watched shorebirds defend beach front during the winter.


Tinbergen, Nikos - (1907 - 1988) - One of the originators of the science of ethology. Won Nobel Prize for Medicine in 1973 along with Konrad Lorenz and Karl von Frisch “- for their discoveries concerning organization and elicitation of individual and social behaviour patterns". Author of The Herring Gull's World. and many other books.


Topography - The parts of a bird. One of the main ingredients to describing a bird is being able to name the various parts. Instead of just naming the wing, you are able to tell the primary from the secondary from the tertial feathers of the wings.


Townsend, John Kirk - (1809 - 1851) Early American ornithologist. Spent time studying birds in the west with Thomas Nuttall. Townsend's Warbler is named after him.


Tundra - A barren, treeless area in the arctic area. Despite its character it is the favorite breeding area for many North American shorebirds.


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Umbrella species - (From Wikipedia) Umbrella species are species selected for making conservation related decisions, typically because protecting these species indirectly protects the many other species that make up the ecological community or its habitat. Species conservation can be subjective because it is hard to determine the status of many species. With millions of species of concern, the identification of selected keystone species flagship species or umbrella species makes conservation decisions easier. Umbrella species can be used to help select the locations of potential reserves, find the minimum size of these conservation areas of reserves, and to determine the compositoin, structure and processes of ecosystems.


Upwelling - Cold nutrient rich water in the ocean that comes from the depths to the surface and is responsible as a food source for many seabirds


Vertebrate - Animals with backbones. This phylum includes five different classes: Fish, Amphibians, Reptiles, Birds and Mammals. One of the most common mistakes made by people (especially people who should know better) is to refer to "Birds and animals." All birds are animals. Not all animals are birds.


Wetlands - From the EPA: "Generally, wetlands are lands where saturation with water is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the soil and on its surface (Cowardin, December 1979). Wetlands vary widely because of regional and local differences in soils, topography, climate, hydrology, water chemistry, vegetation, and other factors, including human disturbance. Indeed, wetlands are found from the tundra to the tropics and on every continent except Antarctica."


Wetmore, Alexander - (1886 - 1978) (From Wikipedia) was an American ornithologist and avian paleontologist. Wetmore was born at North Freedom, Wisconsin and studied at the University of Kansas. He later studied at George Washington University, receiving his masters degree and doctorate. Wetmore began federal service in 1910, working for the Biological Survey of the Department of Agriculture. In 1915, he researched the use of lead shot in causing death in waterfowl. His paleontological research led to his work on the fossil birds Palaeochenoides miocaenus and Nesotrochis debooyi. In 1925 Wetmore was appointed assistant secretary of the Smithsonian Institution, becoming secretary between 1945 and 1952. He wrote A Systematic Classification for the Birds of the World (1930, revised in 1951 and 1960). This Wetmore Order received widespread acceptance, remaining popular until the end of the twentieth century. He died in Glen Echo, Maryland. Some of his writing can be viewed in the natural history accounts of these species: White-winged Dove,


Wilson, Alexander - (1766 - 1813) The author of American Ornithology and considered the father of American ornithology. He named the Chipping Sparrow., and the Wilson's Warbler was named after him. Some of his writing can be viewed in the natural history accounts of these species: Mourning Warbler,



Xeric - a moderately arid habitat; as opposed to a mesic habitat which is moist


Young Bird - The period of time from when the bird is hatched to the time when it reaches sexual maturity. There is a great variety of ways that different species spend this time. One way to view this variety is through the variations of precocial and altricial. The different levels are outlined in an article by Margaret Nice including examples.

Precocials - eyes open, down covered, leave nest first day or two

  1. Independent of parents (e.g. Megapodiidae)
  2. Follow parents but find own food (e.g. Anatidae, Charadriidae)
  3. Follow parents and shown food by them (Phasianidae, in part)
  4. Follow parents and are fed by them (e.g. Podicipitidae, Rallidae).

Semi-precocials - eyes open, down covered, stay at nest until able to walk, fed by parents (e.g. Laridae)

  1. Eyes open (e.g. Ardeidae, Falconfiormes
  2. Eyes closed (e.g. Strigiformes)

Altricials - eyes closed, little or no down, unable to leave nest, fed by parents (e.g. passeriformes)


Zoology - The study of animal life. This includes the study of birds (ornithology), the study of insects (entomology), the study of mammals (mammalogy). It does not include the study of plants (botany). Zoology is a sub-division of biology.

Birds in the Classroom
The Bird Groups
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