Tern sea terns have light grey or white body plumage as adults, with a black cap to the head. The legs and bill are various combinations of red, orange, yellow, or black depending on species. The pale plumage is conspicuous from a distance at sea, and may attract other birds to a good feeding area for these fish-eating species. When seen against the sky, the white underparts also help to hide the hunting bird from its intended prey. The Inca tern has mainly dark plumage, and three species that mainly eat insects, the black tern, white-winged tern, and black-bellied tern, have
California least tern considered conspecific with the little tern. "Sternula albifrons", which has an extensive Old World distribution. The little tern differs from the least tern mainly in that its rump and tail are white, not grey, and it has a different call. California least tern The California least tern, "Sternula antillarum browni", is a subspecies of least tern that breeds primarily in bays of the Pacific Ocean within a very limited range of Southern California, in San Francisco Bay and in northern regions of Mexico. This migratory bird is a U.S. federally listed endangered subspecies. The total population of the subspecies amounted