Swift (Apus apus)
Great Shearwater (Ardenna gravis)
All black swift with small white throat patch. Very difficult to separate from Pallid swift and Plain Swift. Pallid Swift; brownish plumage tone (best seen against darker background), bigger throat-patch than swift, scale pattern on body more prominent, wing-tips slightly rounded, "saddle" darker than wings, and more contrast between darker outer primaries and inner. Plain Swift; throat patch smaller and more diffuse than swift, wings and body more slender, tail noticeably deeper forked.
Sound:A shrilling trill "zreeeee" of about 1 -2 seconds length, gradually rising in pitch with accentuated firs half, then falling from the middle of phrase. Often continued with a dry lower pitched "trrrrrr" before calling again. Very vocal at breeding area, and often a flock will call together. Despite being quite similar to Pallid Swift, the call is probably the best field character to separate the two. Pallid puts the stress on the ending of the call, followed by a quick fall in pitch (dynamics like moaning with a quick release). Plain Swift calls similar to Common Swift, but differs in slightly fluctuating pitch during the call, and a loss of resonance towards the ending (thinner sounding).
Song/contact call:
Distribution:
Wikipedia: map (se also Xeno-canto below)
Ecology:Birdlife ecology
Links:
Observation.org Latest observations
Image search Flickr NB! May give other species
CCLarge shearwater with distinct, marked, dark cap and white collar. Blotched belly and underwings. White upper tail-coverts forms a horseshoe mark, but note that Cory's Shearwater may show the same. Dark patch at side of neck. Bill dark. Flight action powerful, with alternating glides and rapid bursts of beats with stiff wings. Seldom soars.
Sound:Calls at breeding ground a deep, soft, moaning "oooh-aahh" ("surprised or shocked old lady"). Tone fairly clear, and pitch rising and falling.
Distribution:Wikipedia: map (se also Xeno-canto below)
Ecology:Birdlife ecology
Links:
Observation.org Latest observations
Image search Flickr NB! May give other species
CC