Rock Sandpiper
Calidris ptilocnemis
Plump, rock-loving shorebird with slightly droopy bill. Most often seen in nonbreeding plumage, which is fairly dark gray with heavily spotted underparts. Color of legs and base of bill varies from dull greenish to orangey. Breeding plumage shows reddish back and smudgy black belly. Juveniles show some rusty tones and have neat white fringes on wing feathers. Some variation across range; breeding population on Pribilof Islands in Alaska is larger and paler. Breeds on tundra; winters on rocky coastlines, sometimes feeding on mudflats. Typically in flocks in winter, often mixed with turnstones or Surfbird. Extremely similar to Purple Sandpiper but no range overlap.
识别特征
Adults have short yellow legs and a medium thin dark bill. The body is dark on top with a slight purplish gloss and mainly white underneath. The breast is smeared with grey and the rump is black. The Pribilof Islands subspecies of this bird shows a bold black belly patch.
分类信息
The rock sandpiper was formally described in 1873 by the American ornithologist Elliott Coues and given the binomial name Tringa ptilocnemis. It was formerly placed in the genus Erolia, but is now placed with 23 other sandpipers in the genus Calidris that was introduced in 1804 by the German naturalist Blasius Merrem. The genus name is from Ancient Greek kalidris or skalidris, a term used by Aristotle for some grey-coloured waterside birds. The specific epithet ptilocnemis combines the Ancient Greek ptilon meaning "feather" with knēmē meaning "leg". Within the genus Calidris the rock sandpiper is closely related to the sanderling (Calidris alba) and dunlin (Calidris alpina) and is sister to the purple sandpiper (Calidris maritima).<p>Four subspecies are recognised:
- 学名
- Calidris ptilocnemis
- 命名信息
- (Coues, 1873)
- 目
- Charadriiformes
- 科
- Scolopacidae
- 属
- Calidris
分布与栖息地
Birds migrate south to rocky ice-free Pacific coasts in winter. The subspecies leap frog each other for winter, with more northerly breeders passing south of more southerly breeders. It reproduces in tundra habitats, typically favoring drier and more desolate areas with limited vegetation such as lichen, moss, and sparse grasses. It can form rather large wintering flocks.<p>Rock Sandpipers which spend the non-breeding season in the Pacific Basin, Alaska, have to endure harsh conditions where they rely on high prey quality, especially of their primary prey - the bivalve Macoma balthica.
- 繁殖区
- PAL, NA : coastal low Arctic to subarctic tundra of far n Pacific: e Chukotskiy Pen. to (disjunctly) s Kamchatka, Commander and (perhaps) n Kuril is. (e Russia), Aleutian and Bering Sea is., w Alaska from Seward Pen. to Gulf of Alaska is.
- 非繁殖区
- rocky subarctic to temperate coasts: Hokkaido (n Japan, w North Pacific; rare) to c California (e North Pacific)
- 迁徙
- Complete migrants
行为
Their breeding habitat is the northern tundra on Arctic Pacific coast of Alaska and the Aleutian and Pribilof Islands. The birds also breed in Kamchatka and the Kuril Islands. The breeding pair is usually monogamous, with pair bonds usually lasting several years. They nest on the ground either elevated on rocks or in lower damp location. The male makes several scrapes; the female chooses one and lays 4 eggs. Both male and female take the responsibility for incubation.<p>These birds forage on rocky coasts. They mainly eat insects, mollusks, marine worms, also some plant material. It often feeds up to its breast in water, and often swims. It roosts on rocks near its feeding grounds just above the high tide spray.
保护状况
- 种群趋势
- declining
照片
分布
鸟叫声
其他鸟类
Guanay Cormorant
Leucocarbo bougainvilliorum
Locally abundant coastal cormorant of Humboldt Current. The species name is linked to the famous guano islands of Peru. Can be seen as singles, but usually seen in flocks, sometimes many thousands feeding, nesting, and roosting in dense masses or commuting in endless streams. Associates readily with pelicans, boobies, other cormorants, and Inca Terns. Adult is handsome with a distinctive “dinner dress” pattern of white extending up into neck and a red patch around the eye. Immature has similar pattern, but is brownish above and the plumage is duller overall.
Collared Redstart
Myioborus torquatus
Small, active warbler with diagnostic yellow face, dark collar, and orange crown. Flashes white outer tail feathers while foraging for insects. Found in montane forest and edges, often in pairs. Follows mixed feeding flocks, often moving quickly through the middle levels of the trees. Sexes alike.
Striated Bulbul
Alcurus striatus
A well-marked bulbul with a bushy crest. Olive-green above with a pale yellow throat and extensive white streaks on a dark breast and pale belly. A foothill and submontane specialist found in broadleaf forests, both evergreen and deciduous. Forages in the forest canopy, often in the company of other bulbuls. Somewhat similar to Mountain Bulbul, but has a bushier, more erect crest, darker upperparts, and obvious streaking on the underparts. Generally not very vocal; gives various chirps, warbles, and chips, often strung together into a loose “song” with short, distinct phrases.
开始您的观鸟之旅
在户外识别鸟类，并在下一次观察时随手查阅鸟类图鉴。