In breeding plumage this species resembles white-cheeked tern, but is smaller and has a white vent and less a deeply forked tail. In non-breeding plumage it is very similar to white-winged tern, but has a pale grey rump and a grizzled head pattern more closely resembling that of arctic tern. Black tern is darker, with more black on the head and a diagnostic dark shoulder smudge.
Juvenile resembles juvenil arctic tern but the latter has a white (not grey) uppertail, and the two species are unlikely to be seen in the same habitat.
Wide range of open, freshwater bodies, from large lakes and river flood plains to small farm dams.
A repeated, hard 'zizz'.