Most people would be surprised to learn that worldwide there are some 339 species of songbirds who are known to practice vocal mimicry. Australia’s lyrebirds are the unrivalled superstars of mimicry of course, but there are loads of other skilled little mimics in our east coast forests who also deserve recognition. I’ll introduce you to a few shortly. But first, let’s consider why birds mimic.
Songbird mimicry usually consists of perfect, or near-near perfect copes of the calls from other local birds. One exception to this rule are the 22 superb lyrebirds that were introduced to Mount Field in Tasmania between 1934 and 1949. These birds had grown up in southern Victorian forests so when they arrived in Mt Field NP they continued to mimic the calls of pilotbirds and eastern whipbirds, neither of which exist in Tassie. Whipbird mimicry continued in Tassie’s lyrebirds well into the 1960’s, although the call’s quality and fidelity had diminished considerably. By the 1980’s, subsequent generations of lyrebirds had almost entirely forgotten how to do the whipbird’s whipcrack.
No one really understands the full evolutionary purpose of mimicry, although it seems clear that it provides male birds with a way to demonstrate (to females mostly) their intelligence, vitality and age. The older a bird is, the longer it has been around to collect and practice a large repertoire of mimicry sounds. And since practice makes perfect, high-fidelity mimicry of complex sounds from the local environment is likely interpreted by females as standard proof of survival fitness in male birds.
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