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Listen to the gulping sounds of a currawong, the laughs of a kookaburra, or the deafening screeches of a cockatoo and, even with your eyes closed, you would know you are in Australia. We live in a bird-rich continent and, while some of our birds may be unusual to look at, it is their vocalisations that really set them apart. Compared to birds from the northern hemisphere, Australian birds are generally much louder, use a far greater range of notes, and have a propensity to mimic other sounds. This last point is not widely known, even though Alec Chisholm claimed in his book 'Bird wonders of Australia' (1948) that more than 50 Australian bird species can mimic. At least half of the ones he named have since been confirmed (including bowerbirds, butcherbirds, the Australian Magpie and Noisy Miner). Europe may boast its starlings, and North America its mocking birds but, as far as we know, no continent can quite match Australia's record for bird mimics.But what do we mean by mimicry? Sounds, such as alarm calls, are easily shared by many bird species, and birds might have overlapping vocal ranges that make it appear as if one species is mimicking another. Some birds may even incorporate the odd small snippet from another bird's song into their own. But this is not what I mean. By mimicry I am referring to sustained, repeated and unmistakable sounds that are recognisably specific to another species rather than the one using them. |
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