Bare-legged Swiftlet vs Great Dusky Swift
Aerodramus nuditarsus مقارنةً بـ Cypseloides senex
Side-by-Side Comparison
| السمة | Bare-legged Swiftlet | Great Dusky Swift |
|---|---|---|
| الاسم العلمي | Aerodramus nuditarsus | Cypseloides senex |
| الرتبة | Caprimulgiformes | Caprimulgiformes |
| الفصيلة | Apodidae | Apodidae |
| حالة الحفاظ | Least Concern | Least Concern |
| الطول | — | — |
| طول الجناح | 25,0 cm (9.8 in) | 33,8 cm (13.3 in) |
| الوزن | 13,3 g (0.47 oz) | 83,0 g (2.93 oz) |
| النظام الغذائي | 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 … |
| عدد البيض في الوضع | -- | 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.
حالة الحفاظ
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
A small swiftlet (10-11 cm) found in New Guinea, particularly in lowland and hill forests. Distinguished by its bare, featherless tarsi. Dark plumage. Aerial insectivore. Colonial cave nester. Uses echolocation for cave navigation. Limited published ecological data.
Great Dusky Swift
A large swift (18-20 cm) of southeastern Brazil, eastern Paraguay, and northeastern Argentina. Dark sooty-brown plumage. Aerial insectivore, foraging over forested gorges and waterfalls. Nests in large colonies behind waterfalls. The largest member of the genus Cypseloides.