The Whiskered Tern (Chlidonias hybridus) is a seabird of the tern family Sternidae and is the largest of all marsh terns. This bird has a number of geographical races, differing mainly in size and minor plumage details.
C. h. hybridus breeds in the warmer parts of Europe and Asia. The smaller-billed and darker C. h. delalandii is found in east and south Africa, and the paler C. h. javanicus from Java to Australia.
The tropical forms are resident, but European and Asian birds are known to winter south from Africa and southern Asia.
This bird breeds in colonies on inland marshes, sometimes amongst Black-headed Gulls, which provide some protection from predation. It nests in a ground scrape and lays two to four eggs.
As with other the other Chlidonias marsh terns, Black Tern and White-winged Black Tern, Whiskered Tern feeds on insects taken in flight, and not by plunge-diving for fish like the white Sterna terns.
The hybridus in the scientific name arises from the fact that it shows similarities in appearance to both the white Sterna terns and to Black Tern.
The size, black cap, strong bill and more positive flight are reminiscent of the Common or Arctic Tern, but the short tail and dark grey breeding plumage above and below are typically marsh tern characteristics. The summer adult has white cheeks and red legs and bill. The call is a characteristic krekk.
In winter, the forehead becomes white and the body plumage a much paler grey. Juvenile Whiskered Terns have a ginger scaly back, and otherwise look much like winter adults.