By way of summary to my short item on bowerbird mimicry let me state that I
wrote a small, almost innocent observation. I observed a Satin Bowerbird
making the same call as a Whistling Kite.
Replies have been quite instructive so let me tease this out further.
*Where?*
The Satin Bowerbird I observed called its mimicry at a small, isolated patch
of bushland, surrounded by mowed foreshore. It was calling from an exposed
branch in a Casuarina tree some 3 metres above the ground. Below that tree
there is a small pittosporum and native grasses. However there was no bower.
The whole act of mimicry happened on the western foreshore of Lake Macquarie,
at Balcolyn.
Tiffany reported a male mimicking around her workplace. Greg spoke of
another calling from a high eucalypt tree at Gibraltar Range NP and a bird
doing the same within his back yard.
Is there any significance as to where a bird performs?
*When?*
This bird called on Tuesday 11th July at 7.50am. It was a clear, sunny
winter day. No other correspondent referred to time of year or day. Details
about time (of day and year) might unlock much about this behaviour.
*By what?*
I did not have binoculars. I could not tell if I was looking at an immature
male or a female. It was not a satin blue. Most note that the only mimics
they have observed were satin blue mature males but Greg referred to a
female mimic in his piece. Tiffany referred to a young male. I presume it
was in immature plumage.
*Calling what sounds?*
I referred to a Whistling Kite. Others have spoken of Grey Butcherbird
(Colin), Currawongs, Red Wattlebirds, White-winged Choughs, Yellow-tailed
Black-cockatoos and Magpie (Tiffany), Wedge-tailed Eagle and Yellow-Tailed
Black Cockatoo (Greg) and Grey Goshawk (Syd). If you add in the other
various sounds I see no particular pattern here.
*Why?*
I did not attempt this. I merely reported the observation. Others have
posited:
1. Territorial defence mechanism (Colin)
2. Joy (Tiffany)
Now who would defend territory? And what type of territory? Is this a
feeding or breeding territory? And if so, why imitate the rolling of biscuit
tins?
There are some more questions to be answered.
--
Brian Everingham
PO Box 269
Engadine
NSW 2233
Australia
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