Australian Bush Birds
Caspian Tern  -  Hydroprogne caspia
Caspian Tern
Adult Caspian Tern on the Darling river at Wentworth, NSW showing the prominent red bill with dark tip. The white 'streaks' on the head indicate a non-breeding bird.
Caspian Tern
Immature Caspian Tern, with buff-brown markings on the body. Younger, immature birds have a dull orange bill.
map map The Caspian Tern - Hydroprogne caspia - is the largest of the terns characterised by a large, red bill. Crown, nape and forehead are black to below the eye and sometimes reaching the bill. Back, shoulders, upper wings and forked tail are silver-grey; tips of outer primary wing feathers are dusky. Underparts and underwing are white. Eyes are dark brown, Bill is red with darker tip, feet black. Male and female are similar. Grows to 540 to 580 millimetres.

Immature birds are similar to adults in colour but with buff-brown marks on the upper body; the bill is dull orange.

Non-breeding adult birds have extensive white markings on the black head; the black 'cap' of breeding adults is smaller

In flight, the long wings are darker underwing near the tip; the tail is short, white and slightly forked.

Caspian Tern - page 2
The Caspian Tern is found in salt and fresh water around the entire Australian coast as well as inland over the eastern half of the continent and in Tasmania. As well as more sheltered coastal waters this bird is found on beaches, mudflats, estuaries, larger rivers, reservoirs and lakes. In flight uses powerful, regular wingbeats while patrolling the surf line and inshore waters at heights between 10 and 20 metres. The bill typically points down. Eats mainly fish up to 18 centimetres long. When prey is seen the bird turns, folds it wings and plunges into the water, sometimes it hovers briefly before diving.

Common but scattered and not concentrated. Usually solitary or in pairs; some adults may be sedentary on prime feeding territory while other adults, and immature birds, seem to be nomadic.

Breeds from September to December in the south, any time in the north. Single nests or small colonies. The nest is a bare scrape on the ground. One or two eggs are laid; matt stone-grey or light brown in colour; blotched sparingly grey-brown and black; long-oval, about 65 by 45 millimetres. Incubated for 20 to 22 days by both parents. Chicks are brooded in the nest for a few days before being led off to cover under low vegetation. When defending the nest or chicks the parents pive a skim past intruders screaming as they fly.

Widespread globally; found in Eurasia, Africa, North America and New Zealand. One race found in Australia.

 ¶  Genus Hydroprogne is in Family Laridae containing the Gulls, Terns and Noddies. There is considerable scientific debate over whether the Caspian Tern should be included in genus Sterna with many other terns or should be separated as Hydroprogne; different sources have taken different approaches at different times so the species may be listed as Hydroprogne caspia or as Sterna caspia. Opinion presently favours the former name.