Little Swift
Apus affinis
Little swifts are readily identified by their small size. Their wingspan is only 33 cm compared to 42 cm in the case of common swift. Their plumage is black except for a white throat and rump, the white rump patch extending onto the flanks. They have a short square tail, with all rectrices round-tipped. The flight is fluttering like that of a house martin, and the call is a high twittering. Like other swifts they are very short-legged. The legs are used for clinging to vertical surfaces only.
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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