Imperial Cormorant
Leucocarbo atriceps
Very striking cormorant readily identified by white neck. Locally common black-and-white cormorant of colder coastal waters. Often seen perched on inshore rocks and jetties, sometimes with Magellanic Cormorant. Nests colonially on low islands (rarely in lakes inland from coast) and jetties. Plumage varies regionally, with some birds black-faced and others white-faced; the two types breed together locally in the Strait of Magellan. Immature resembles adult but plumage duller overall, brownish above.
识别特征
The imperial shag has a total length of 70–79 cm (28–31 in) and weighs 1.8–3.5 kg (4.0–7.7 lb), with males usually larger than females. It is endowed with glossy black feathers covering most of its body, with a white belly and neck. It possesses a distinctive ring of blue skin around its eyes, an orange-yellow nasal knob, pinkish legs and feet, and an erectile black crest. During the non-breeding season, adults lack the crest, have a duller facial area, and less/no white to the back/wings. It has a serrated bill used for catching fish.<p>The group varies primarily in the amount of white on the cheeks/ear-coverts, wing-coverts and back. Most taxa have white cheeks and ear-coverts, but these are black in albiventer, purpurascens and melanogenis. Chicks are uniform brownish, and immatures are brownish and white (instead of black and white), have dull facial skin, and lack the orange-yellow nasal knob and blue eye-ring.
分类信息
The taxonomy is very complex and species-limits within this group remain unresolved. Some taxonomic authorities, including the International Ornithologists' Union, split the group into the species listed below. Others consider all or part of the group conspecific. The following are considered part of this group:<p>While some authorities consider all of the above – except albiventer – as separate species, others consider all as subspecies of a single species (as done in this article). Alternatively, some recognize two species, the white-cheeked L. atriceps (with subspecies bransfieldensis, nivalis and georgianus) and the black-cheeked L. albiventer (with subspecies melanogenis and purpurascens), or it has been suggested that three species should be recognized: L. atriceps (including albiventer), L. georgianus (with subspecies bransfieldensis and nivalis), and L. melanogenis (with subspecies purpurascens and possibly verrucosus, though the latter is relatively distinctive, and most consider it a separate species, the Kerguelen shag).
- 学名
- Leucocarbo atriceps
- 命名信息
- (King, PP, 1828)
- 目
- Suliformes
- 科
- Phalacrocoracidae
- 属
- Leucocarbo
分布与栖息地
- 迁徙
- Complete migrants
行为
This is a colonial, monogamous species. The colonies are usually relatively small, but some consist of hundreds of pairs and are often shared with other seabirds such as rock shags, southern rockhopper penguins and black-browed albatrosses. Up to five eggs (usually two or three) are placed in a nest made of seaweed and grass, and cemented together with mud and excrement. The eggs usually hatch in about five weeks, and are brooded by both parents. Many chicks and eggs are lost to predators such as skuas and sheathbills.<p>The diet of this species consists of small benthic fish, crustaceans, polychaetes, gastropods and octopuses. They primarily feed on fish, especially Argentine anchoita,. Mean diving depth is almost 25 m (82 ft), and they have been filmed diving as deep as 60 m (200 ft) to forage on the sea floor. Most feeding takes place in inshore regions, but at least some populations will travel some distance from the shore to fish.
保护状况
- 种群趋势
- unknown
照片
分布
鸟叫声
其他鸟类
Long-billed Gnatwren
Ramphocaenus melanurus
Very small bird of humid tropical forest and edge. Favors vine tangles at mid-upper levels, where moves actively, holding its tail cocked and flopping it from side to side. Appearance is distinctive, with buffy face, very long thin bill, and fairly long tail with white tips. Similar to Chattering Gnatwren but lacks the extra white spots on outer tail feathers. Easily overlooked, but rising and falling trilled song reveals its presence.
Great Barbet
Psilopogon virens
This largest of the barbets is colorful, but often appears all-dark from a distance. No other barbet in its range combines the features of a massive pale bill, black head, and dark olive back. Sluggish and shy; tends to stick to dense forest canopy, where it is difficult to see. Its loud hooting song (typically a series of two repetitive notes) is often the only indication of this species’s presence. Also gives a harsh, screaming “karrrrr” that has a gull-like quality.
Shelley's Oliveback
Nesocharis shelleyi
A unique, beautiful finch of forest, forest edge, and farmlands, found only in the highlands of Cameroon, Equatorial Guinea, and extreme southwest Nigeria. Surprisingly compact, with a short, stubby tail and a thick bluish bill. Shows a black head, a yellow-green back and wings, and gray undersides. Males also have a yellow-green chest. Feeds acrobatically on small branches, ferns, and other vegetation in the understory and sometimes higher, alone or in small groups. Calls are high pitched “siew” notes, and the song is a sequence of high-pitched buzzy notes.
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