Great Crested Tern

The great crested tern, also called the greater crested or swift tern, nests in dense colonies on coastlines and islands in the tropical and subtropical Old World, from South Africa round the Indian Ocean to the central Pacific and Australia. It has dark grey upperparts, white underparts, a yellow bill and a shaggy black crest that recedes in winter. Its darker battleship-grey upperparts, white forehead in full breeding plumage and greenish-yellow bill separate it from close relatives (Wikipedia, general species account).

It plunge-dives for fish, and the male offers fish to the female in courtship. It follows fishing boats for discarded bycatch and uses unusual nest sites such as roofs and artificial islands. Young birds are strongly patterned and are fed by their parents for months after fledging.