Black-headed Duck
Heteronetta atricapilla
An uncommon and easily overlooked small duck of lakes and wetlands, usually with surrounding reeds. Mainly seen singly or in pairs, sometimes in small groups, and at times sleeping with Lake Ducks. Note the long and low profile in the water and the long gray bill with a pink band at the base on males. Males have a black head, but females are notably drab brownish overall and are best identified by size and shape, and association with a male. Lays its eggs in nests of other birds, such as coots, ducks, and even herons. Ducklings fend for themselves.
识别特征
The black-headed duck is the most basal living member of its subfamily, and it lacks the stiff tail and swollen bill of its relatives. Overall much resembling a fairly typical diving duck, its plumage and other peculiarities indicate it may not be a very close relative of the other stiff-tailed ducks, but rather the product of convergent evolution from the ancestors of the stiff-tailed ducks.<p>The black-headed duck is about 35 cm (14 in) long. Males weigh an average of about 510 g (18 oz) and females 565 g (20 oz). The species has a distinctive shape, with a long body and disproportionately short wings. Its bill has a black maxilla and an orange mandible; the maxilla has a rosy patch at its base during the breeding season. Adult males have a glossy black head and upper neck and a white chin. Their upperparts are deep brownish black with cinnamon or pale rufous speckles and vermiculation. The folded wing shows two white bars. Their underparts are whitish with brown mottling and appear silvery. Adult females have a dark brown head and neck and a whitish throat, and are otherwise like the male. Immature birds are similar to the female but have more rufous upperparts, more yellowish underparts, and a pale eye stripe.
分类信息
The black-headed duck is the only member of genus Heteronetta and has no subspecies. It is closely related to the "stiff-tailed" ducks of genera Nomonyx, Oxyura, and Biziura.
- 学名
- Heteronetta atricapilla
- 命名信息
- (Merrem, 1841)
- 目
- Anseriformes
- 科
- Anatidae
- 属
- Heteronetta
分布与栖息地
The black-headed duck has two separate ranges. One is the western side of central Chile. The other is from extreme southern Bolivia south through central Paraguay to central Argentina and east through southern Uruguay into southernmost Brazil. Undocumented sight records in the Falkland Islands lead the South American Classification Committee of the American Ornithological Society to treat it as hypothetical there. It mostly inhabits freshwater marshes whose dominant plant is the sedge Scirpus californicus, and outside the breeding season may be found in lakes, water-filled ditches, and sometimes flooded fields.
- 迁徙
- Complete migrants
行为
The black-headed duck is partially migratory. It is a year-round resident in most of its range but is found in most of Paraguay and its small Bolivian range only in the non-breeding season.<p>The black-headed duck feeds by diving. Though little information is available about its diet, a major component appears to be seeds of Scirpus californicus, and snails a minor component.<p>The black-headed duck is unique among waterfowl; it is an obligate brood parasite. The female does not build a nest but lays its eggs in the nests of other birds. Known hosts include the rosy-billed pochard (Netta peposaca), the red-fronted coot (Fulica rufifrons), and the red-gartered coot (F. armillata). At least 18 other species have been reported as hosts, including several other waterfowl and rail/coot species, the brown-hooded gull (Chroicocephalus maculipennis), and a few raptors. Unlike some cuckoos, neither the chicks nor adults destroy the eggs or kill the chicks of the host. In contrast with brood parasitic passerines, whose young are altricial, black-headed duck ducklings are precocial. After an incubation of about 25 days, the ducklings are completely independent a few hours after hatching and leave the nest.<p>The black-headed duck is usually silent. It does give a low "quah quah" as part of a courtship display, and also "a two note grunt followed by a whistle: – gr-rump-freet." Females make "clucking notes."
保护状况
- 种群趋势
- stable
照片
分布
鸟叫声
其他鸟类
Sabah Partridge
Tropicoperdix graydoni
Intricately-patterned partridge of tropical lowland rainforest. Uncommon and declining throughout its range. Brown with buff scaling, rusty bib, stippled black-and-white head pattern, and a pale throat. Forages in small flocks on the forest floor. Found at lower altitudes than other partridges in range and distinguished by pale ear patch and lack of rufous on the head. Song, often given as a duet, consists of loud, tremulous whistles followed by a series of up and down notes “weep! churrrrr…!”.
Aztec Rail
Rallus tenuirostris
Large, chickenlike rail of fresh marshes in highlands. Heard more often than seen; its main call is a rhythmic dry chatter. No similar large rails in its range. Note the large size, rusty neck and breast, barred flanks, and long, mostly orange beak. Virginia Rail is much smaller, with blue-gray cheeks.
Lesser Racket-tailed Drongo
Dicrurus remifer
An ebony shadow trailing obsidian tresses. Medium-sized drongo with two extravagantly long tail feathers tipped with plumes, the shape of which vary throughout its range. Glossy black overall with red eyes. Juvenile duller and lacks streamers. Can be confused with the larger Greater Racket-tailed Drongo, but Lesser is crestless and oddly flat-headed, with a more square-ended tail. Inhabits mid- to high-altitude tropical forests, where it forages primarily under closed canopies, not venturing out into the open as frequently as Greater Racket-tailed. Joins mixed flocks. Impressive vocal range, giving highly variable songs that include bouncy hoots, ringing whistles, and harsh nasal notes, among others; also mimics other species.
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