Apus pallidus
Very similar to Common Swift, and often difficult to identify in the field. Seeing the birds against a darker background, as opposed to the sky, brings out some of the characters more clearly. Generally paler and more sandy brown than Common Swift. Differs further from C. Swift by: Rounder wing tip (outermost primary shorter than the next), slightly broader wings, broader and flatter head. White throat patch bigger and more prominent. The face seems paler, which brings out the dark eye-mask. Back slightly darker than upper part of wings. More contrast between outer and inner primaries. Underparts with more pronounced scaly pattern. Flight less acrobatic, with slightly slower wing-beats, more frequent gliding and much less twinkling turns.
Similar to Common Swift, but usually very helpful for ID. Almost di-syllabic, with marked accent on second syllable which rapidly drops in pitch, "srrrree-aah". Common swift has a more even call, with accents on first part, without the sudden pitch-drop.
Xeno-canto: map
Birdlife ecology
Sound recording:Creative Commons,www.xeno-canto.org,Carlos W.,http://creativecommons.org/licenses/by-nc-sa/4.0/
