Greater Crested Terns

A rather distant shot of a party of Greater Crested Terns Thalasseus bergii standing on a sand bar along with Common Terns Sterna hirundo, a Little Tern Sternula albifrons and Brown-headed Gulls Chroicocephalus brunnicephalus.

Greater Crested Tern, also called Crested Tern or Swift Tern, is a seabird which nests in dense colonies on coastlines and islands in the tropical and subtropical Old World. Its five subspecies breed in the area from South Africa around the Indian Ocean to the central Pacific and Australia, all populations dispersing widely from the breeding range after nesting. This large tern is closely related to Royal and Lesser Crested Terns, but can be distinguished by its size and bill colour.

Reference: Wikipedia