Bare-legged Swiftlet vs Great Dusky Swift
Aerodramus nuditarsus 对比 Cypseloides senex
Side-by-Side Comparison
| 属性 | Bare-legged Swiftlet | Great Dusky Swift |
|---|---|---|
| 学名 | Aerodramus nuditarsus | Cypseloides senex |
| 目 | Caprimulgiformes | Caprimulgiformes |
| 科 | Apodidae | Apodidae |
| 保护状况 | Least Concern | Least Concern |
| 体长 | — | — |
| 翼展 | 25.0 cm (9.8 in) | 33.8 cm (13.3 in) |
| 体重 | 13.3 g (0.47 oz) | 83.0 g (2.93 oz) |
| 食性 | Obligate aerial insectivore; catches minute flies, beetles, and aerial spiders while foraging near cave roosts. | Feeds on aerial plankton of tiny insects and spiders; entire diet captured during non-stop aerial … |
| 产卵数 | -- | 1-2 |
| Population Trend | — | — |
Habitat Comparison
Song & Call Comparison
Bare-legged Swiftlet
High thin twittering; 'tsit-tsit' over New Guinea lowlands; echolocation clicks in cave roosts; calls weakly in flight; colonial nester producing soft flock chattering
Great Dusky Swift
Loud, churring trill; harsher and louder than other Cypseloides; calls over Iguacu Falls and major Neotropical waterfalls; buzzy 'bzzzt-bzzzt' in aerial groups
Geographic Range & Migration
Bare-legged Swiftlet
Found in lowland New Guinea and adjacent islands. Resident in lowland rainforest and forest edge. Little-known Papuan endemic.
Great Dusky Swift
Found in eastern South America from Venezuela and the Guianas south to Bolivia and Paraguay. Resident near rocky cliffs and waterfalls.
保护状况
Bare-legged Swiftlet
Great Dusky Swift
How to Tell Them Apart
Bare-legged Swiftlet
Small; dark grey-brown upperparts; pale rump band; underparts whitish-grey; forked tail; bare unfeathered tarsi distinctive among swiftlets; New Guinea lowland cave-nesting species; bare legs visible at nest but rarely field-observable.
Great Dusky Swift
Very large; entirely dark sooty-brown with pale grey forehead and chin scaling; slightly paler underparts; broad wings; largest Cypseloides swift; South American waterfall specialist with dusky uniform plumage and imposing …
About These Birds
Bare-legged Swiftlet
一种小型金丝燕（体长10-11厘米），分布于新几内亚，尤其集中于低地和丘陵森林。属雨燕科（Apodidae），以跗跖裸露无羽为鉴别特征。
Great Dusky Swift
大暗色雨燕分布于巴西和阿根廷，在大型瀑布附近繁殖的雨燕。