Yes Marnix - trillers and songlarks are good
examples. Perhaps the best example is the W-browed Wswallows (sometimes
with Masked) when they appear - maybe every 3 years. On 4
occasions in S Canberra esp Callum Brae I have seen large numbers suddenly
arrive and feed in company, before they move on abruptly, leaving maybe a dozen
nesting pairs in a good year and in a poor year only a couple. It is as
if the main cohort exhausts the readily available food and has to move on to
maintain itself. I wonder if the stayers represent more mature bids or
more strongly bonded pairs. There are a few relevant obs noted in HANZAB
including from Canberra. No sign of a woodswallow horde as yet this
spring. One view is that such influxes are pushed by dry conditions
to west, which might not exist this year.
From: Marnix Zwankhuizen
[
Sent: Friday, 23 October 2009 3:10 PM
To: 'Dimitris Bertzeletos'; canberra birds
Subject: RE: [canberrabirds] 2) Rufus Songlarks, 1) White-winged Triller
at ANU [SEC=UNCLASSIFIED]
UNCLASSIFIED
Hi,
I have found over the years from my own observations that many
summer migrants peak early on in spring. Many appear on passage in less
suitable areas but only stay briefly before moving on. Only a percentage will stay
on in more suitable areas to breed.
However, this spring has been a wet one and maybe more of them
will stay around in these areas this summer.
Cheers,
Marnix Zwankhuizen | Assistant Director
IT Solutions | Information Technology
Australian Electoral Commission
T: 02 6271 4465 | F: 02 6271 4644
UNCLASSIFIED
From: Dimitris Bertzeletos
[
Sent: Friday, 23 October 2009 2:18 PM
To: canberra birds
Subject: [canberrabirds] 2) Rufus Songlarks, 1) White-winged Triller at
ANU
Hello all,
Just got home from Uni and there was a pair of Rufus Songlarks in the upper
reaches of Sullivan's Creek (in the park directly opposite ANU campus). There
was also a calling White-winged Triller in the willows there.
Cheers!
Dimitris
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