The koels are still going strong in Page as well. We have at least three: an
adult male; an immature male; and at least one but more likely two females.
This morning both adults dropped into a neighbour's liquidamber and were
urged out by the resident wattlebirds; they then tried a nondescript large
bush nearby and were discouraged by a pair of Magpie-larks. The male is
currently doing the rounds of his favourite perches, koelling steadily. They
don't appear to be sampling prunuses but the adult male has been seen
tucking into loquats. In terms of breeding success, I'd be more than
surprised if we don't score a koel chick somewhere nearby as the adults have
been so persistent over several weeks, despite there being fewer host nests.
b
-----Original Message-----
From: Michael and Janette Lenz
Sent: Friday, 10 December 2010 7:41 PM
To: David McDonald; chat line
Subject: Impacts of rain on breeding success?
David,
Just a few comments and a bit of speculation, no science.
>From my days in Germany it was evident that wet summers meant poor breeding
success in many species, notably the aerial feeders (swifts, swallows,
martins), and species with open cup nests. There are difficulties in finding
sufficient food (for the parents, let alone the young) and keeping the nest
content dry and warm. Prolonged wet weather can be very energy-demanding
particularly when 're-fuelling' is difficult.
Here I have found the Pied Currawong to be quite sensitive to wet
conditions, with fewer young reaching fledgling stage than were in the nest
at the start (incl. finding dead young under the nest). This year I have not
seen many young P. Currawongs, and if so, at the most 2 young/pair. At the
recent December woodland survey at Mt Ainslie I saw only a few fledglings
from any species, and I assumed that the very wet weather has reduced
breeding success (but several species were still on nests, several of those
were most likely replacement brood attempts). Even the Dusky Woodswallows
(Jack Holland's nest workshop in Campbell Park in mid November showed them
as abundant), were no longer very evident. Also there are only few
indications of breeding success in the wider surroundings of my GBS site in
Lyneham, on Lyneham Ridge etc. incl. common species (e.g. Magpie, Red
Wattlebird) (a key exception so far are the Noisy Miners at the ANU; they
seem to be indestructible!).
Even species which may have "dry" nest sites, incl. many cavity nesters, may
still be experiencing difficulties in finding enough food (e.g. Dollarbird,
Rainbow Bee-eater and others) with consequences for their overall breeding
success.
I have also been wondering why Koels have only given brief, fleeting
appearances this year in some of the areas where they have been breeding
successfully in the past (e.g. Ainslie, Lyneham). Is this also weather
related? Perhaps a reflection of limited numbers of suitable host nests at
the right stage/time for dropping eggs in? With the mild winter/spring and
some early welcome rains, several species have started nesting earlier than
usual, this would have been followed by difficult conditions for follow-up
broods (e.g. Red Wattlebird, Magpie-lark, Noisy Friarbird, potential hosts)?
We also have to keep in mind that rainfall in different parts of Canberra
can vary greatly; hence conditions and circumstances are not uniform across
town. What may apply to some parts of our area, may not be relevant in
others.
Michael Lenz
--------------------------------------------------
From: "David McDonald" <>
Sent: Thursday, December 09, 2010 4:48 PM
To: "CanberraBirds" <>
Subject: Impacts of rain on breeding success?
> Hi, I'm wondering what science tells us about the impacts of extended wet
> periods, such as we are now experiencing, on bird breeding success, and
> the mechanisms involved. Anyone out there on top of this topic?
> Thanks - David
>
> --
> David McDonald
> Canberra Ornithologists Group email lists manager
> T: 02 6238 3706
> M: 0416 231 890
> E:
>
>
>
>
****************************************************************************
***************************
> This is the email announcement and discussion list of the Canberra
> Ornithologists Group.
> Please ensure that emails posted to the list are less than 100 kb in size.
> When subscribing or unsubscribing, please insert the word 'Subscribe' or
> 'Unsubscribe', as applicable, in the email's subject line.
> List-Post: <>
> List-Help: <>
> List-Unsubscribe: <>
> List-Subscribe: <>
> List archive:
> <http://bioacoustics.cse.unsw.edu.au/archives/html/canberrabirds>
> List manager: David McDonald, email
> <>
>
****************************************************************************
***************************
|
