|Australian Bush Birds|
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|Crested Tern - Sterna bergii|
|Crested Tern resting on a rock. The lemon-yellow (sometimes orange-tinted) bill is characteristic. The black cap indicating breeding status is subdued in this non-breeding bird.|
|Crested Tern showing breeding black cap extending forward below the eye, the crest at the back of the head is also visible. Two silver gulls are preening on the left. (Urunga, NSW)|
The Crested Tern - Sterna bergii - is an overall grey and white bird with a prominent lemon-yellow, very slightly curved down, bill (sometimes tinted orange). When breeding it has a black cap with short, shaggy crest at the rear and extending in front to the bottom of the eye. Bill is slightly curved down, lemon-yellow. Below cap is white including white band above base of bill. Underside and breast are white, wings and back are pale grey. Wings are long and tail is forked. Legs and feet are black. Reaches 40 to 50 centimetres. Male and female are similar.
Breeding birds have a well defined black cap; in non-breeding birds the front of the cap moves nearer to the top of the head and the front edge is poorly defined.
Immature birds are similar to non-breeding adults with a dirty lemon coloured bill and blotched dusky and white on the shoulders and flight feathers.
|Crested Tern - page 2|
Common large tern on bays and harbours (second largest Australian tern after the Caspian Tern). Often roosts on boats and jetties or rests on sand beaches or isolated rocks. May be in mixed flocks with gulls and other terns.
Common bird around the Australian coast. Lives along the coast on ocean beaches, estuaries and coastal lagoons. Occasionally on salt lakes. In ones and twos to flocks of 50 or more birds, it rests on sand spits, low points and reefs along coastal beaches and inlets. Rarely flies far from shore out to sea or inland on bodies of fresh water. Distributed around the Australian coast, including Tasmania.
Searches for fish while in flight at height of five to 15 metres with bill pointing down looking for small surface fish five to eight centimetres long. Plunges down to take prey just under the water surface, grabbing the fish behind the head. Eggs and baby turtles are sometimes taken as well.
|Crested Tern showing non-breeding black cap receded well back from the eye-line. The Crested Tern's black cap is not often seen as far receded as this. (Urunga, NSW)|
|Crested Terns gathered on low-tide sandy beach near Cape Woolamai, Philip Island. Most birds are busy preeening.|
|Crested Tern - page 3|
Gathers in colonies of up to several thousand birds to breed on offshore islands all around the coast. Breeds September to December in the east and south, March to June in the north and in both time periods in the west. Colonies continually vary is locations, times and numbers from year to year. In courtship a bird offers a fish to its mate with crest erect and wings trailing; the mate parades around then both birds fly off, one behind the other in a spiralling formation flight reaching to 200 metres.
The nest is a depression in sand or shingle, often among low plants. Nests are spaced a bit more than metre apart, just beyond pecking distance. One egg (rarely two) is laid; slightly glosssy stone-grey with sepia, red-brown and black streaks; oval, about 61 by 41 millimetres. Incubated by both parents for about 25 to 26 days. One, or both, parents brood the young until they are strong enough to join creches. After fledging the young disperse far from the parental colony; some have been recorded half-way around the continent.
¶ Genus Sterna is in Family Laridae containing the Gulls, Terns and Noddies. This genus contains the typical terns in the family.
|Crested Terns gathered on low-tide sandy beach; the distinctive profile and strong bill are easy to see.|