Stercorarius longicaudus
Breeding plumaged adults with streamers unmistakable (streamers comprising two thirds of total tail length). Adult plumage shows less variation than in other skuas. No hint of breast band, and transition between pale belly and darker vent very diffuse. No white patches at base of primaries of underwing in adults. Juveniles easily confused with juvenile Arctic Skua, but are more slender. Wings narrower and primaries and tail longer. Juvenile Arctic Skua shows white patches at base of primaries on both sides of wings, juvenile Long-tailed only on underwing, and on first few primaries of upper. Barred rump and tail coverts in juveniles. Flight elegant and buoyant.
Calls sharp and less full-bodied than Arctic Skua, and not so mewing. Short, double-accented "kew-wev" or short "kerk" in agitation. Also a long drawn-out "keeeeaah", resembling both Arctic Skua and Common Gull.
Wikipedia: map (se also Xeno-canto below)
Birdlife ecology
Sounds:Recorded by Andrew Spencer,http://www.xeno-canto.org ,CC license
