The Caspian Tern is a large tern, easily distinguished by the massive bright red/orange bill and graceful flight on long shapely wings. The upper body is pale grey, the top of the head is black with white streaks while the neck and underparts are white. When breeding the top of the head is black and the streakiness is lost. Young birds have mottled upperparts.
It is seen in pairs or alone, cruising along the edge of the breakers or in the Barwon Estuary. Their nests are deep scrapes, sometime edged by saltbush and scraps of other bushes. They usually feed by hovering above the water and then diving into the water to catch fish. They feed mainly on fish.