Australian birdsAustralia has about 800 species of bird, ranging from the tiny 8 cm Weebill to the huge, flightless Emu.
To the visitor from the northern hemisphere, many will immediately seem familiar - Australian wrens look and act very like northern hemisphere wrens, Australian robins seem to be close relatives of the northern hemisphere robinss - but in fact the majority of Australian passerine birds are descended from the ancestors of the crow family, and the close resemblance is misleading: the cause is not genetic relatedness but convergent evolution.
For example, almost any land habitat offers a niche for a small bird that specialises in finding small insects: the form best fitted to that task is one with long legs for agility and obstacle clearance, moderate-sized wings optimised for quick, short flight, and a large, upright tail for rapid changes of direction. In consequence, the unrelated birds that fill that niche in the Americas and in Australia look and act as though they were close relatives.
Very broadly speaking, Australian birds can be classified into four categories:
- Long-established non-passerines of ultimately Gondwanan origin, notably emus, cassowaries and the huge parrot group.
- Passerines peculiar to Australasia, descended from the corvid family, and now occupying a vast range of roles and sizes. Examples include wrens, robins, Magpies, thornbills, pardalotes, the huge honeyeater family, treecreepers, lyrebirds, birds of paradise and bowerbirds.
- Relatively recent colonists from Eurasia, including swallows, larks, thrusheses, cisticolas, sunbirds, and some raptors.
- Birds recently introduced by humans: some, like the European goldfinch and greenfinch coexist happily, others such as European Common Starlings, Blackbirds and sparrows and the Indian Mynah are destructive vermin.