Neotropic Cormorant
Nannopterum brasilianum
Black body. Immatures have dark brown breast. Orange facial skin comes to a point and is bordered by thin white line. Smaller, longer-tailed and shorter-legged than Double-crested Cormorant. Dives underwater to capture fish. Often perches with spread wings to dry them out. Most widespread species of cormorant from Mexico south. In U.S., seen mostly in Texas.
识别特征
This bird is 64 cm (25 in) long with a 100 cm (39 in) wingspan. Adult males weigh from 1.1 to 1.5 kg (2.4 to 3.3 lb), adult females 50 to 100 g (1.8 to 3.5 oz) less. Birds of the southern populations tend to be bigger than the more northerly birds. It is small and slender, especially compared to the larger, heavier-looking double-crested cormorant. It has a long tail and frequently holds its neck in an S-shape. Adult plumage is mainly black, with a yellow-brown throat patch. During breeding, white tufts appear on the sides of the head, there are scattered white filoplumes on the side of the head and the neck, and the throat patch develops a white edge. The upper wings are somewhat grayer than the rest of the body. Juveniles are brownish in color.
分类信息
The neotropic cormorant was documented in 1658 by the Dutch naturalist Willem Piso after travels in Brazil. This formed the basis for the formal description and naming of the species by Johann Friedrich Gmelin in 1789. He placed it with the petrels in the genus Procellaria and coined the binomial name Procellaria brasiliana. Many authors preferred to use Alexander von Humboldt's 1805 description of Pelecanus olivaceus because the identity of Piso's birds was considered uncertain. Later, ornithological authorities such as the American Ornithologists' Union began to use Phalacrocorax brasilianus after Ralph Browning argued that Piso's description and paintings do indeed refer to the neotropic cormorant.<p>The neotropic cormorant was formerly placed in the genus Phalacrocorax. A molecular phylogenetic study of the cormorants published in 2014 found that the neotropic cormorant, the double-crested cormorant, and the flightless cormorant formed a clade that was sister to the genus Leucocarbo. The three species were, therefore, moved to the resurrected genus Nannopterum that had been introduced in 1899 by English ornithologist Richard Bowdler Sharpe to accommodate the flightless cormorant. The genus name Nannopterum combines the Ancient Greek nannos meaning "dwarf" with pteron meaning "wing".<p>Two subspecies are recognised:
- 学名
- Nannopterum brasilianum
- 命名信息
- (Gmelin, JF, 1789)
- 目
- Suliformes
- 科
- Phalacrocoracidae
- 属
- Nannopterum
分布与栖息地
- 迁徙
- Resident species
行为
Unlike other cormorants, this bird can often be seen perching on wires.<p>Its diet consists mainly of small fish, but will also eat tadpoles, frogs, aquatic insects (such as dragonfly nymphs), and shrimp. Information about its prey is sparse, but inland birds seem to feed on small, abundant fish in ponds and sheltered inlets, less than 10 cm (3.9 in) in length, with an individual weight of a gram or two, such as Poecilia species especially the sailfin molly Poecilia latipinna. This cormorant forages for food by diving underwater, propelling itself by its feet. Its dives are brief, between 5 and 15 seconds. It is also known to forage in groups, with several birds beating the water with their wings to drive fish forward into shallows.<p>Neotropic cormorants are monogamous and breed in colonies. The nest is a platform of sticks with a depression in the center circled with twigs and grass. It is built a few meters above the ground or water in bushes or trees. Up to five chalky, bluish-white eggs are laid. Most pairs lay three eggs, but the mean number hatched is less than two. The eggs soon become nest-stained. Both sexes incubate for about 25–30 days, and both parents feed the young until around the 11th week. By week 12, they are independent. One brood is raised per year.<p>This bird is largely a permanent resident, with some birds occasionally wandering north in the warmer months.
保护状况
- 种群趋势
- rising
照片
分布
鸟叫声
其他鸟类
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Dicaeum maugei
A tiny, short-tailed songbird. Male is glossy-black above with a scarlet rump, and whitish below with a striking red throat bordered black and a black stripe running down the belly. Female is dull gray above with a red rump and whitish underparts. Juvenile resembles female, but pale-billed. Singles and pairs can be found in forest, forest edge, woodlands, and plantations in lowlands and foothills. Male differs from male Blood-breasted Flowerpecker in white underparts and black border below throat. Female Red-chested Flowerpecker is paler above than female Blood-breasted. Gives a very high-pitched song, “tzit-wut-zoo,” lower-pitched on the last note. Also gives short, sharp “tzit” calls.
White-bearded Greenbul
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Sharpe's Akalat
Sheppardia sharpei
Small, fairly plain, brown-and-orange robin-like bird. The tail is uniformly rufous-brown and the face shows a pale-gray eyebrow. Found locally in the understory of montane forest. Very shy and inconspicuous. The song is a quick, tripping series of high whistles. Also gives an alternating series of high-pitched piping notes and low-pitched scolding trills. Similar in size, shape, and behavior to Iringa and Usambara Akalats, but distinguished by orange underparts.
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