Black Scoter
Melanitta americana
Plump diving duck, typically seen in flocks in coastal areas. Males are completely black with bright orange knob on the bill. Females are brown overall with pale cheek and contrasting dark cap. Note potbellied shape and rounded head in flight. Typically coastal, but migrates over land especially in the Northeast U.S. Often gathers in tight flocks. Dives frequently, feeding on aquatic invertebrates. Breeds on ponds in Arctic tundra.
识别特征
This large sea duck is characterised by its bulky shape and large bill. The adult male is all black with a very bulbous bill which is mostly yellow. The female is a brown bird with pale cheeks, very similar to female common scoter. The adult female averages about 980 g (2.16 lb) and 45 cm (18 in) in length, while the adult male is on average 1,100 g (2.4 lb) and 49 cm (19 in) in length.<p>This species can be distinguished from other scoters, apart from common scoter, by the lack of white anywhere on the drake, and the more extensive pale areas on the female.<p>The black scoter and common scoter have diagnosably distinct vocalisations.
分类信息
- 学名
- Melanitta americana
- 命名信息
- (Swainson, 1832)
- 目
- Anseriformes
- 科
- Anatidae
- 属
- Melanitta
分布与栖息地
The black scoter breeds in the far north of North America in Labrador and Newfoundland to the southeast and northwest of Hudson Bay. It also occurs on the Siberian side of the Bering Straits east of the Yana River. It winters farther south in temperate zones, on the coasts of the northern USA and Canada, on the Pacific coast south to the San Francisco Bay region and on the Atlantic and Gulf of Mexico coasts, and in Asia as far south as China.<p>Some birds may over-winter on the Great Lakes. This species is a very rare vagrant to western Europe; only drakes are safely identifiable out of range, so females are likely to be undetected.
- 繁殖区
- PAL, NA : Yana River to Kamchatka (e Siberia), Alaska e to nw Yukon; e Northwest Territories and sw Nunavut to Newfoundland (c to e Canada)
- 非繁殖区
- to c Japan (w North Pacific coast); Aleutian Is., e North Pacific coast to c California; Newfoundland to n Florida (w North Atlantic coast)
- 迁徙
- Complete migrants
行为
This species dives for crustaceans and molluscs while migrating or wintering on the sea-coasts, and feeds on insects and their larvae, especially caddisflies, fish eggs and, more rarely, vegetation such as duck weed while nesting on freshwater. It forms large flocks on suitable coastal waters in winter quarters. These are tightly packed, and the birds tend to take off together; in the breeding season they are less social. It has been suggested that in coastal waters this species prefers sheltered embayments, and possibly waters that include some mixed depths.<p>Black scoters nest later than most other ducks in North America. Pairs form in late winter or spring. The lined nest is built on the ground close to the sea, lakes or rivers, in woodland or tundra. 5–7 eggs are laid. Each eggs weighs from 60–74 g (2.1–2.6 oz), or 8% of the females body weight. The incubation period may range from 27 to 31 days. Females brood their young extensively for about 3 weeks, after which the still flightless young must fend for themselves.<p>The male performs a diagnostic downward head movement when stretching his wings.
保护状况
- 种群趋势
- declining
照片
分布
鸟叫声
其他鸟类
Pale-footed Swallow
Orochelidon flavipes
Uncommon swallow in montane forest in the Andes from Venezuela to Bolivia. Similar to the more common Blue-and-white Swallow, but look for the buffy throat and browner flanks on Pale-footed Swallow. Found in flocks, usually not far from forest. Not frequently found around human settlements unlike Blue-and-white Swallow. Occurs from around 2,400–3,200 m.
Sargasso Shearwater
Puffinus lherminieri
Small black-and-white shearwater with relatively long tail and somewhat rounded wings. Usually flies low to the water with fluttering wingbeats, but in strong winds it can fly with high wheeling arcs. Undertail coverts are typically dark, but this can be very difficult to see in the field. Compare with Manx Shearwater, which is larger with longer, more pointed wings, light undertail coverts, and a darker face. Found over warm tropical waters, especially around floating mats of Sargassum weed. Often seen singly or in pairs but can gather in loose flocks, sometimes loafing with other shearwater species.
Red-legged Partridge
Alectoris rufa
Distinctive gamebird of farmland, grassy fields, and open heathland. Seen mainly as pairs and small groups, often along the edges of fields. Plumage is ornate and handsome, with a red bill, white throat, black streaked necklace, boldly barred flanks, and buffy belly. Other similar species (such as Chukar) do not overlap in native range, but can escape from collections or be introduced for hunting; all lack the diagnostic black-streaked necklace of Red-legged. Song is a dry, rasping “wa-cha-cha-wa-cha-cha” or “wi’ch-ch’ch.”
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