House Swift
Apus nipalensis
The house swift looks quite similar to the little swift. It is a small bird, but a medium-sized swift, with a wingspan of 12.5-14.5 cm. Its body size ranges from 14 to 16 cm and weighs approximately 20-35 g. This species has a dark, slightly forked tail. Other than the white rump band and white throat-patch, the house swift has a black plumage, darker than the little swift. Voice: House swifts make a ti-ti-ti-tititrrrrrr sound, among many others, as part of their vocal catalogues.
ID text from Wikipedia, CC BY-SA 4.0
Pallid Swift
Apus pallidus
This 16–17 cm (6.3–6.7 in) long species is very similar to the common swift, and separation is only possible with good views. Like its relative, it has a short forked tail and very long swept-back wings that resemble a crescent or a boomerang. It is entirely dark except for a large white throat patch which is frequently visible from a distance. It is chunkier and browner than common swift, and the slightly paler flight feathers, underparts and rump give more contrast than that species. It also has a scalier looking belly and subtly different flight action.
ID text from Wikipedia, CC BY-SA 4.0
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