| Australian tern | |
|---|---|
 | |
| Australian tern at Cairns, Queensland | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Charadriiformes |
| Family: | Laridae |
| Genus: | Gelochelidon |
| Species: | G. macrotarsa |
| Binomial name | |
| Gelochelidon macrotarsa (Gould, 1837) | |
TheAustralian tern orAustralian gull-billed tern (Gelochelidon macrotarsa) is atern in the familyLaridae, native toAustralia. The genus name is fromAncient Greekgelao, "to laugh", andkhelidon, "swallow".
John Gould describedSterna macrotarsa from a specimen held at King's College, London in 1837.[2] Although first described as a species, throughout most of the 20th and early 21st centuries it was generally considered to be asubspecies of thegull-billed tern,[3] but was re-elevated to species status by theIOC World Bird List in 2019 in its Version 9.2.[4]
This is a fairly large and powerful tern, similar in size and general appearance to aSandwich tern, but the short thickgull-likebill, broad wings, long legs and robust body are distinctive. The summer adult has pale grey upperparts, white underparts, a black cap, strong black bill and black legs. The call is a characteristicker-wik. It is 33–42 cm (13–17 in) in length and 76–91 cm (30–36 in) in wingspan.[5][6] Its weight ranges from 150–292 g (5.3–10.3 oz).[7] It differs from the closely relatedgull-billed tern in being slightly larger, paler grey above, and with an obviously larger, heavier bill.[8]
In winter, the cap is lost, and there is a dark patch through the eye like aForster's tern or aMediterranean gull. Juvenile Australian terns have a fainter mask, but otherwise look much like winter adults.
It breeds inAustralia, with some also reachingNew Guinea in the non-breeding season.
This species breeds in colonies on lakes, marshes and coasts. It nests in a ground scrape and lays two to five eggs.
This is a somewhat atypical tern, in appearance like aSterna tern, but with feeding habits more like theChlidonias marsh terns,black tern andwhite-winged tern.
The Australian tern does not normally plunge dive forfish like the other white terns, and has a broader diet than most other terns. It largely feeds on insects taken in flight, and also often hunts over wet fields and even in brushy areas, to take amphibians and small mammals.[5] It is also an opportunistic feeder, and has been observed to pick up and feed on dead dragonflies from the road.[9]
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