Gull-billed Tern (Gelochelidon nilotica)
Parasitic Jaeger (Stercorarius parasiticus)
Easily confused with Sandwich Tern but choice of habitat usually different. Adults differs by noticeably shorter and deeper bill, lacking yellow tip. Wings are broader, tail is shorter and only slightly forked. Lacks crest. Primaries with dark trailing edge, especially underside. Rump pale grey, and there is no contrast between grey back and white tail as in Sandwich Tern. Loses the black cap in winter, but keeps a black mask (less black on head than Sandwich T). Immature birds also gives a paler impression. The back is almost uniform in colour, and the wings also have only diffuse markings. The dark trailing edge to the primaries is present though, together with dark eye mask. Rest of head is pale. Flight slightly front-heavy with shallow wing-beats. Catches insects in the air and from the ground in flight. Rarely plunge-dives. Prefers fresh water, and is often seen near wetlands, rivers and flooded fields, but also in salt water during migration.
Sound:Quite vocal and easily distinguished from most congeners. Mewing and sharp in tone, but not rattling or raucous like most terns. Most typical call is a disyllabic, mewing "ke-waat", with an upward inflection. Other variants are series of "ke-ke-ke-ke", or the mewing sounds.
Contact call:
Distribution:
Xeno-canto: map
Ecology:Birdlife ecology
Links:
Observation.org Latest observations
Image search Flickr NB! May give other species
CCDark, pale and intermediate morphs. Pale birds more common in northern parts of species range, darker morphs more common further south. Elongated middle tail feathers (projection comprising about half the total tail length), but not as long as in adult Long-tailed skua. White patches at base of primaries, both on upper and underside of wings. Dark morph chocolate brown with darker hood. Pale morph with white throat and belly and incomplete breast band. Relatively marked transition from pale belly to dark vent (as opposed to Long-tailed). Size close to Common Gull. Flight powerful, elegant and falcon-like. Juveniles with short but pointed middle tail-feathers. Confusion with other juvenile skuas very likely. Differs from Long-tailed in prominent white base of most primaries on upper side of wing (not just the first few feathers). Lacks the double white patch of Pomarine Skua's underwing, and shows less contrast between back and rump. Wings broader than Long-tailed but narrower than Pomarine. Approximately equal to distance from wing rear edge to tail-tip (projections excluded).
Sound:Mostly heard at breeding ground. Most characteristic call is a mewing, kittiwake-like "aeeeee-ah". First syllable drawn-out and rising in pitch, and followed by a deeper conclusive second syllable "ah". Lacks the introductory double accent of Kittiwakes ("kitti-wake").
Alarm call/flight 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
CCSounds:Recorded by Fernand Deroussen,http://www.xeno-canto.org ,CC license