At 14:17 23/10/2000 +1100, you wrote:
>Thanks for posting your report Peter.
>
>Can I ask you a question.
>
>Why do the raptor numbers fall after the winter period?
>
>
>Thank you
>
>
>Paul
>
>
Hi Paul
It is mainly the Whistling Kites, and to some extent the Brahminy Kites,
that show these seasonal changes. (They are the dominant species anyway).
On my standard route, raptor numbers go from c. 230 in winter to 60 or less
in summer. This pattern has repeated for two years in S. Moreton Bay and
for two years previously in Pumicestone Passage to the north.
Why ? These are just guesses at this stage and other suggestions would be
welcome.
Most of these raptors breed in winter, presumably when food is most
available. This may be associated with fish, like bream, spawning at this
time.
Maybe food becomes scarce in summer and they have to move on.
Where to they go - who knows?
If it were just the Whistlers, we could suggest that they might be moving
inland
but that would be less likely to apply to the Brahminy Kites.
Just a few of life's many mysteries.
Cheers
Pete
Dr Peter Woodall email =
Division of Vet Pathology & Anatomy
School of Veterinary Science. Phone = +61 7 3365 2300
The University of Queensland Fax = +61 7 3365 1355
Brisbane, Qld, Australia 4072 WWW = http://www.uq.edu.au/~anpwooda
"hamba phezulu" (= "go higher" in isiZulu)
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