At 06:04 PM 4/25/98 +1000, Klaus Uhlenhut wrote:
We pushed the cars out of the garage (no fumes!), we
>snake-proofed the nest sites, and all without success. The young kept on
>disappearing.
Hi Klaus,
How did you snake-proof the nest sites? Did it still allow other potential
predators [e.g. small mammals, birds (both conspecifics and other species)]
access to the nest? I just feel that their nest may not have been totally
predator-proof, especially as young were disappearing.
The breeding pair may also been inexperienced breeders, even though they
have attempted to rear young over at least 3 years. Breeding success in
many Australian bird species tends to increase with experience, and often
pairs do not successfully produce any fledglings at all from their first
breeding attempts. It seems that many breeding birds need time and those
early experiences of failure to learn how to successfully raise a family.
If the parents weren't feeding the nestlings, this suggests that either:
(1) they didn't know how to; (2) it wasn't worth the effort to feed them
because the nestlings were likely to die; (3) the parents didn't/couldn't
make frequent visits to the nest because of disturbances (presence of
predators, humans?); (4) they couldn't find enough food to deliver to the
nest.
Maybe the young were born weak or physically disadvantaged because they had
deleterious genes? Maybe the young were diseased?
... just a few suggestions. I'm sure that others will add some more.
Best wishes,
Stephen
************************************************************
Dr Stephen Ambrose
Research Manager
Birds Australia (Royal Australasian Ornithologists Union)
Australian Bird Research Centre
415 Riversdale Road,
Hawthorn East,
VIC 3123.
Tel: +61 3 9882 2622
Fax: +61 3 9882 2677
Email:
1997 Australian Bird Research Directory is on Birds Australia's
home page: <http://www.vicnet.net.au/~birdsaus>.
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