Bufflehead
Bucephala albeola
Small, compact diving duck with large head and small gray bill. Breeding males are black and white with large white patch on back of head. Females and immature males are gray-brown with white patch on cheek. Much smaller than Common Goldeneye with which it often associates. Found in bays, estuaries, reservoirs, and lakes in winter. Travels to boreal forest and nests in cavities in summer.
识别特征
The bufflehead ranges from 32–40 cm (13–16 in) long and weighs 270–550 g (9.5–19.4 oz), with the drakes larger than the females. Averaging 35.5 cm (14.0 in) and 370 g (13 oz), it rivals the green-winged teal as the smallest American duck. The bufflehead has a wingspan of 21.6 in (55 cm).<p>Adult males are striking black and white, with iridescent green and purple heads and a large white patch behind the eye. Females are grey-toned with a smaller white patch behind the eye and a light underside.
分类信息
- 学名
- Bucephala albeola
- 命名信息
- (Linnaeus, 1758)
- 目
- Anseriformes
- 科
- Anatidae
- 属
- Bucephala
分布与栖息地
They are migratory and most of them winter in protected coastal waters, or open inland waters, on the east and west coasts of North America and the southern United States. They can also be observed wintering on the Great Lakes. The bufflehead is an extremely rare vagrant to western Europe. Their breeding habitat is wooded lakes and ponds in Alaska and Canada, almost entirely included in the boreal forest or taiga habitat. From 1966 - 2015, the bufflehead experienced a >1.5% yearly population increase throughout its breeding range.
- 繁殖区
- NA : subarctic wc Alaska and Canada e to e Quebec and (locally) nw, nc USA
- 非繁殖区
- to c Mexico and n Florida
- 迁徙
- Complete migrants
行为
Buffleheads have evolved their small size to fit the nesting cavity of their "metabiotic" host, a woodpecker, the northern flicker. Due to their small size, they are highly active, undertaking dives almost continuously while sustained by their high metabolism. They do not tend to collect in large flocks; groups are usually limited to small numbers. One duck serves as a sentry, watching for predators as the others in the group dive in search of food. Buffleheads are amongst the last waterfowl to leave their breeding grounds and one of the world's most punctual migrants, arriving on their wintering grounds within a narrow margin of time.<p>Buffleheads are monogamous, and the females may return to the same nest site, year after year. They nest in cavities in trees, primarily aspens or poplars, using mostly old flicker nests, close (usually < 25 m (82 ft)) to water. Nest competitors include mountain bluebird (Sialia currucoides), tree swallow (Tachycineta bicolor), and European starling. There was one recorded instance of a female Barrow's goldeneye killing a bufflehead adult female and her brood. Smaller cavities are preferred because of less competition with the larger goldeneyes. Females may be killed on the nest by mammals, such as foxes (Vulpes and Urocyon sp.), weasels (Mustela and Neogale sp.) or mink (Neogale vison), and by goldeneyes over nest competition.<p>Average clutch size is nine (range six to 11), and eggs average 50.5 by 36.3 mm (1.99 by 1.43 in). Incubation averages 30 days, and nest success is high (79% in one study) compared to ground-nesting species like the teal. A day after the last duckling hatches, the brood leaps from the nest cavity. The young fledge at 50–55 days of age. Predators of adults include the peregrine falcon (Falco peregrinus), snowy owl (Bubo scandiacus), bald eagle (Haliaeetus leucocephalus), golden eagle (Aquila chrysaetos), red-tailed hawk (Buteo jamaicensis), great horned owl (Bubo virginianus), and Cooper's hawk (Accipiter cooperii).<p>These diving birds forage underwater. They prefer water depths of 1.2–4.5 m (3.9–14.8 ft). In freshwater habitats, they eat primarily insects, and in saltwater, they feed predominantly on crustaceans and mollusks. Aquatic plants and fish eggs can often become locally important food items, as well.
保护状况
- 种群趋势
- rising
照片
分布
鸟叫声
其他鸟类
Golden-fronted Woodpecker
Melanerpes aurifrons
Medium-sized woodpecker, plain buffy-brown overall with black-and-white barring on the back. Head pattern varies across range but usually shows some combination of yellow and red. Most males on the Caribbean slope of Mexico and into Central America have a solidly red crown and nape. In flight, look for white rump. Common and conspicuous in open woodlands, deciduous forest, and arid scrub from Texas and Oklahoma south to Nicaragua. Often the default woodpecker close to human settlements. Visits backyards and feeders, especially for oranges and jelly. Hybridizes with Red-bellied Woodpecker at the northern limits of its range and with Hoffmann’s Woodpecker at the southern limits. Also compare with the smaller Yucatan Woodpecker.
Yellowish Pipit
Anthus chii
Rather dull buffy ground-dwelling bird with a large but disjunct range from Panama to Argentina. Streaky brown above and paler below with a streaked breast and plain belly. Note long pinkish legs and white outer tail feathers. Found in any flat open habitat including savannah, agricultural areas, and desert. Most often seen on the ground, occasionally perched up on a small shrub or fence. The only pipit in most of its range. Listen for the distinctive song, a few tick notes followed by a long descending buzzy “tzeeeeeeew,” often given in flight.
Scaly Thrush
Zoothera dauma
Large thrush with black-edged golden “scaly” feathering. Distinctive in much of range, but a source of consternation in areas overlapping with closely related White’s Thrush; taxonomy and distinguishing characteristics still not completely resolved. Song is a disjointed series of halting ringing notes, often including harsher, buzzier elements; very different from whistles of White’s Thrush. Breeds in hill and montane forests and winters at lower altitudes in forests and forest edge.
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