Further to:
> From: "Margaret Cameron" <>
> Date: Fri, 2 Apr 2010 09:03:21 +1000
> To: "michael norris" <>, <>
> Subject: Re: [Birding-Aus] Mimicry by Grey Butcherbird and others (was Grey
> Butcherbird mimicry)
>
> It is a puzzle to me - and, I find, to real ornithologists - why they do it.
> When I was a beginner birdwatcher in Sydney I remember Alec Chisholm
> collecting mimicry records; he maintained that the Chestnut-rumped Heathwren
> was the best.
My old (and long-departed) mate Alec Chisholm devotes one chapter of his
book "Bird Wonders of Australia" (Angus & Robertson, 1948) to "Stealers of
Sound" - bird mimics.
He dismisses several theories as to the purpose of the mimicry, for example:
- regarding the mimicry as threats: 'keep off my territory' (R. W. G.
Hingston in "The Meaning of Animal Colour and Adornment"). Chisholm:
"Imagine the lordly Lyrebird issuing a warning to a bird smaller than a
sparrow. ... And imagined the Heath-Wren, a tiny bird of the ground,
mimicking the voice of a Swallow (which it frequently does) to warn off a
bird that never descends to the heath."
And Chisholm's final conclusion was: "On the whole therefore, I believe
that birds mimic because they are sound lovers, and because song is their
chief means of expressing their vitality, their high spirits, their joy in
life. What right have we to presume that man is the only creature on earth
that loves to play with "sounds and sweet airs".
Consistent with that view, is a peculiar aspect of Albert's Lyrebird vocal
behaviour. In the breeding season, the males consistently call from the
roost at dawn while waiting for there to be enough light for safety on the
ground under the closed canopy of their predominantly rainforest habitat.
Their performance consists almost entirely of territorial songs: mimicry is
primarily for attracting females for mating, and they aren't aiming to
attract them to the forest canopy. The t. songs from the roost serve to tell
the world in general, and other lyrebirds in particular, that the individual
is alive and well and in command of his territory.
But on a number of occasions, I have recorded performances where instead of
just the normal territorial song, the male gives a delightful range of
variations of it. "Variations on an original air for unaccompanied syrinx"
in musical terminology. :-)
And there seems no reason for it, other than for the 'musical'
enjoyment/satisfaction of the individual himself.
Quoting Chisholm again (in '48, remember): "At present the list of
Australian birds known to use vocal mimicry, either consistently or
casually, includes no fewer than fifty-two species."
And,
"... Australia contains more bird mimics than any other land. It
certainly contains a greater number of consistent mimics than either Europe
or America ..."
Cheers
Syd
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