MIMICRY

I don't know whether more Australian birds mimic than birds from other lands, but we certainly have a lot of mimics here. Everyone knows about lyrebirds imitating other birds and other sounds. We assume that this is the male endeavouring to impress any female within hearing distance. Why would she be impressed by his accurate impression of a car alarm? And lyrebirds are not the only birds to mimic. I'm told that many small passerines will mimic when they're in the hand. Are they frightened? Are they mimicking something big and scary to intimidate the person holding them? Not many honeyeaters mimic, but Regent Honeyeaters do. Why should just one honeyeater do this? Regents mimic wattlebirds and friarbirds (amongst others). In fact Little Wattlebirds are conned: they respond to the Regent's imitation. Australian Magpies mimic, although perhaps it is surprising that, for such a common bird, a bird I see every day, I've only ever been aware of them mimicking twice. The first time was some years ago at a park in Western Australia, when a bird imitated an entire race call, including the crowd reaction. I was spellbound. I'd never heard such a thing before - or since for that matter. I don't recall if the park was close to a raceway. The second time was quite recently, when a house was being built over the road from where I live and a magpie mimicked power tools. The clear conclusion is that not all magpies mimic. Just some individuals are that way inclined. What inspires them?

Other than this, I have two fascinating mimicking recollections. Well, I think that they're fascinating. The first was at Lake Gilles Conservation Park in South Australia when I was on a Peter Waanders tour and he was using callback tape to attract Copperback Quailthrush. A bird responded to the tape and we all believed it was a quailthrush. But not Peter. He said that it didn't sound quite right. We tracked the call down, and, of course, Peter was right. It was not a quailthrush. It was a Striated Pardalote mimicking a quailthrush! It certainly seemed to be calling in response to Peter's tape, but why would a bird do that? The second occasion was very recently when I was looking for Striated Grasswren at Yathong Nature Reserve in New South Wales. I thought I heard a grasswren, but it turned out to be an Inland Thornbill mimicking the grasswren's call. The thornbill called before I played the tape. I was excited and thought the thornbill must have learnt the call from grasswren. Therefore I must be close to my quarry. As far as I could tell, of the several Inland Thornbills present, just two individuals were mimicking grasswren calls. And, of course, I saw not a hint of any grasswren anywhere.

Inland Thornbills are well known mimics. This lovely photo is by Ken Haines. I am sure that if I had a better ear for bird calls, I'd recognize a lot more mimics. I suspect there are a lot of mimics out there. I'd love to know why birds mimic. I reckon there might just be as many reasons as there are birds mimicking. We will probably never know!