The National Audubon Society has identified more than 20 US birds, once common, whose numbers have plummeted since the mid-1960s. All 20 birds on the national Common Birds in Decline list lost at least half their populations in just four decades.
- Eastern Meadowlark Sturnella magna: Characteristic of grassy fields and prairies, the population of Eastern Meadowlarks has declined by 66% to about 10 million individuals. They mainly eat arthropods, but also seeds and berries.Like many grassland birds, meadowlarks are threatened by changes in farming.
- Bobolink Dolichonyx oryzivorus: The population of the Bobolink, which nests in hayfields and other northern U.S. grasslands, has fallen to about 11 million birds—half its earlier numbers. Bobolinks forage on, or near the ground, and mainly eat seeds and insects.
- Short-eared Owl Asio flammeus: This owl no longer nests in many of the grasslands where it used to breed, and its population has decreased by 69 percent, to about 2.4 million birds.
- Greater Prairie-Chicken Tympanuchus cupido: The Greater Prairie-Chicken has disappeared completely from many states; in only a few of them are the 700,000 birds left stable or increasing in population.Their diet consists primarily of seeds and fruit but during the summer they also eat insects and green plants.
- Northern Bobwhite : Numbers of this bird have dropped by more than two-thirds, to about 9 million individuals; it has mostly vanished from the northeastern states. The Northern Bobwhite's diet consists of seeds, and insects that vary with the season.
- Painted Bunting Passerina ciris: This colorful bunting is also a target of the caged-bird trade, exacerbating the problem of habitat loss. Its population has dropped by half, to 4.5 million birds. The Painted Bunting eats seeds, spiders, insects, and caterpillars.
- Florida Scrub-Jay Aphelocoma coerulescens: Because of burgeoning suburbs, there are only about 10,000 Florida Scrub-Jays today, less than 10 percent of the pre-European population. Florida Scrub-Jays are omnivorous, and eat a wide variety of acorns, seeds, peanuts, insects, tree frogs, turtles, snakes, lizards, and young mice.
- Pine Siskin Carduelis pinus: While this finch is still common at many backyard feeders, its numbers have dropped by more than half, to about 22 million birds. They mainly eat seeds, plant parts and some insects.
- Wood Thrush Hylocichla mustelina: Today Wood Thrushes, known for their beautiful song, number 14 million—about half as many as there were 40 years ago. Soil invertebrates and larvae make up most of the Wood Thrush's omnivorous diet, but it will also eat fruits in the late summer, fall, and late winter.
- Cerulean Warbler: Threatened by mountaintop mining in Appalachian forests, this bird has seen its population—about 560,000—drop to less than a quarter of what it was. These birds mainly eat insects.
- Northern Pintail Anas acuta: Even as other duck species are rebounding, this elegant dabbler has declined by 63 percent, to 7.5 million individuals. During the nesting season, this bird eats mainly invertebrate animals, including aquatic insects, molluscs and crustaceans.
- Black Oystercatcher Haematopus bachmani: Though its rate of decline is unknown, this bird of western rocky coasts is sensitive to disturbance, and now numbers fewer than 9,000. It forages in the intertidal zone, feeding on marine invertebrates.
- Common Nighthawk Chordeiles minor:Though able to breed on city rooftops throughout North America, this species’ population has dropped by half, to about 11 million birds. Common Nighthawks catch flying insects on the wing, mainly foraging near dawn and dusk.
- Chimney Swift Chaetura pelagica: This swift nests in yards and chimneys across the eastern United States, yet its population has plummeted 44 percent, to about 15 million birds. These birds live on the wing, foraging in flight. They eat flying insects.
North American bird species undergoing the greatest population declines from 1966 to 2003, Species with large sample sizes (more than 95 routes included in the analysis):
1 Rusty Blackbird Euphagus carolinus: -97.9%; 2003 population estimate: 2,000,000. Emerging dragonflies and their larvae are important food items during the summer.
2 Henslow's Sparrow Ammodramus henslowii: -96.4%; 2003 population estimate: 79,000. These birds forage on the ground, mainly eating insects and seeds.
3 Common Tern Sterna hirundo: -90.6%; 2003 population estimate: 1,400,000
4 Verdin Auriparus flaviceps: -85.6%; 2003 population estimate: 8,900,000. Verdins are insectivorous
5 Sprague's Pipit Anthus spragueii: -83.8%; 2003 population estimate: 870,000. Sprague's Pipit's eat various insects, spiders, and sometimes seeds. During the breeding season the adults are almost entirely insectivorous and feed the young on insects as well.
6 Pinyon Jay Gymnorhinus cyanocephalus: -82.5%; 2003 population estimate: 4,100,000. The seed of the Pinyon pine is the staple food but they supplement their diet with fruits and berries. Insects of many types are also eaten and sometimes caught with its feet
7 Short-eared Owl Asio flammeus: -80.3%; 2003 population estimate: 2,400,000
8 Cerulean Warbler Dendroica cerulea: -79.6%; 2003 population estimate: 560,000. They forage actively high in trees, sometimes catching insects in flight. These birds mainly eat insects.
9 Black-throated Sparrow Amphispiza bilineata: -79.6%; 2003 population estimate: 27,000,000. It feeds primarily on insects and seeds.
10 Loggerhead Shrike Lanius ludovicianus: -77.1%; 2003 population estimate: 4,200,000. Its food is large insects and lizards.
11 Grasshopper Sparrow Ammodramus savannarum: -77.1%; 2003 population estimate: 15,000,000. They forage on the ground in vegetation, mainly eating insects, especially grasshoppers, and seeds.
12 Olive-sided Flycatcher Contopus cooperi: -73.2%; 2003 population estimate: 1,200,000. They wait on a perch at the top of a tree and fly out to catch insects in flight.
13 Baird's Sparrow Ammodramus bairdii: -73.2%; 2003 population estimate: 1,200,000. They forage on the ground, mainly eating insects in summer and seeds in winter.
14 Canyon Wren Catherpes mexicanus: -70.0%; 2003 population estimate: 660,000. It feeds on insects and spiders.
15 Field Sparrow Spizella pusilla: -68.8%; 2003 population estimate: 8,200,000. These birds forage on the ground or in low vegetation, mainly eating insects and seeds.
16 Northern Bobwhite Colinus virginianus: -67.6%; 2003 population estimate: 9,200,000
North American bird species undergoing the greatest population declines from 1966 to 2003, Species with small sample sizes (fewer than 96 but more than 19 routes included in the analysis):
1 Lesser Yellowlegs Tringa flavipes: -97.3%; 2003 population estimate: 500,000. They mainly eat insects, small fish and crustaceans.
2 King Rail Rallus elegans: -94.8%; 2003 population estimate: 63,000. These birds mainly eat aquatic insects and crustaceans
3 Black Swift Cypseloides niger: -93.9%; 2003 population estimate: 150,000. They eat flying insects, primarily flying ants and beetles.
4 Harris' Hawk Parabuteo unicinctus: -88.1%; 2003 population estimate: 390,000. The diet consists of small creatures including birds, lizards, mammals, and large insects.
5 Bendire's Thrasher Toxostoma bendirei: -86.1%; 2003 population estimate: 170,000. They feed on small ground-dwelling insects.
6 Mottled Duck Anas fulvigula: -86.1%; 2003 population estimate: 690,000. They mainly eat plants, but also some mollusks and aquatic insects.
7 Black-chinned Sparrow Spizella atrogularis: -85.6%; 2003 population estimate: 390,000
8 Greater Prairie-Chicken: -78.8%; 2003 population estimate: 690,000
9 Purple Gallinule Porphyrio martinica: -77.9%; 2003 population estimate: < 500,000. The diet is omnivorous, being known to include a wide variety of plant and animal matter, including seeds, leaves and fruits of both aquatic and terrestrial plants, as well as insects, frogs, snails, spiders, earthworms and fish.
10 Horned Grebe Podiceps auritus: -70.0%; 2003 population estimate: < 500,000. It pursues its fish prey underwater.
The following species face the highest possible threats to survival, according to the bird conservation initiatives (Partners in Flight, U.S. Shorebird Council, Waterbirds for the Americas):
Eskimo Curlew Numenius borealis. They ate mostly berries while on the fall migration in Canada. During the rest of their migration and on the breeding grounds they ate insects. Snails and other invertebrate were also part of their diet during migration.
Gunnison Sage-Grouse Centrocerus minimus. These birds forage on the ground. They mainly eat sagebrush, but also insects and other plants.
Black-capped Vireo Vireo atricapilla. These birds are insectivorous, with beetles and caterpillars making up a large part of the diet.
Red-cockaded Woodpecker Picoides borealis. The Red-cockaded Woodpecker feeds primarily on ants, beetles, cockroaches, caterpillars, wood-boring insects, and spiders, and occasionally fruit and berries.
Ivory-billed Woodpecker Campephilus principalis. The Ivory-billed Woodpecker feeds mainly on the larvae of wood-boring beetles, but also eats seeds, fruit, and other insects.
Bicknell's Thrush Catharus bicknelli (winter season). The thrush's diet consist mainly of insects, but wild fruits are added in late summer, during migration, and on the wintering grounds. They usually forage on the forest floor, but also catch flies, and glean insects from the foliage of trees
Bachman's Warbler Vermivora bachmanii. Its primary prey included caterpillars, spiders, and other arthropods.
Golden-cheeked Warbler Dendroica chrysoparia. Warblers eat insects and spiders.
Kirtland's Warbler Dendroica kirtlandii (winter season). These birds eat insects and some berries, also eating fruit in winter.
Piping Plover Charadrius melodus. They mainly eat insects, marine worms, and crustaceans.
Founded in 1905, Audubon is one of America's most prominent conservation groups.
National Audubon Society
The Huffington Post, 06/23/11, article by David Yarnold, 10th president of the National Audubon Society. http://www.huffingtonpost.com/david-yarnold/what-birds-teach-us-dont-_b…
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