Thanks Geoffrey, good graphic, though I don't understand the grey arrows.
Mynas and Dollarbirds coexisting as residents might be related to the
Dollarbird also seeming to be a pugnacious bird and well capable of
competing with Mynas. I was watching a pair of Galahs fussing
around a nest hollow in CBrae for quite some time. The Galahs
seemed to own the hollow and invested a lot of effort on it over an hour,
until a single Dollarbird flew up and cleared the Galahs out in less than
a second, no argument at all. The Dollarbird did not seem to be
using it and just flew away afterwards but maybe was staking a
claim. My interpretation being that if a Dollarbird is capable of
easily dominating two Galahs, then even Mynas might not be a problem for
them.
At 11:09 AM 3/01/2010, Geoffrey Dabb wrote:
A most informative graphic,
thank you Julian. I've not been to Corroboree Park and must pay a
visit. It seems to be a major centre of activity. I wonder if
I shall not see more birdwatchers than actual corroboree
participants?
On the question of neighbours, the below barely-decipherable offering is
an attempt to superimpose the dollarbird map from HBW on the (now-dated)
Common Myna distribution in John Long's 'Introduced Birds of the World'.
The exercise faces the difficulty that different projections are used
which changes both the shape of the land masses and their relationship to
one another. If you can work it out, it shows that in the breeding
season the DB does indeed overlap introduced pockets of the resident
detested myna in Australia. However the birds know one another from
elsewhere. In parts of SE Asia and southern India the 2 are
residents side by side. There is an area in southern China where
resident mynas are invaded by dollarbirds on their summer expeditions
northwards.
Incidentally, this is an example of a species with a significantly
non-Australian distribution which now bears an Australian-origin standard
name. According to Gould (who called it ?Australian Roller?) it was
a ?Dollar Bird? to the ?Colonists?. The other example I can think
of is ?Swamphen?.
-----Original Message-----
From: Julian Robinson
Sent: Sunday, 3 January 2010 12:35 AM
To: canberrabirds chatline
Subject: Bad neighbours, Corroboree Park
I thought a picture of the nesting Dollarbirds in Corroboree Park was
posted recently, but can't find it. The Dollarbirds have been
nesting for at least two weeks and I went to check them out again
today. The neighbours are a bit sad, not Noisy but Common.
The left nest was in the adjacent tree to the Dollarbirds, and the other
one is 20-30m away. Maybe CIMAG should do some more selling in the
area, or is it one of the control areas in current Myna studies?
Incidentally a SC Cockatoo was trimming a strip of bark from in front of
a hollow on the recently lopped tree there. Hopefully the tree will be
hosting nests again sooner than some of us thought. Maybe it was the
hollow previously used by the Gang-gangs.
Julian
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