White-winged Tern

The white-winged tern, or white-winged black tern, is a small tern generally found in or near fresh water across much of Europe, Africa, Asia and Australia. Summer adults have short red legs, a short black bill, a black body and neck, a white rump and light grey tail, and mainly white wings. In non-breeding plumage most of the black is replaced by white or pale grey, though black shows on the underwing coverts. The head is black with a white forehead in winter and the crown is flecked with white (Wikipedia, general species account).