Apart from the obvious size factor, surely there is simply the food factor
as well. It is hard to imagine koel chicks ingesting bits of flesh offered by a
raptor feeding them.
On 28/12/18, 2:03 pm, "Philip Veerman" <> wrote:
Cuckoos parasitise species smaller than themselves. Maybe that is
needed to get the chicks the ability to push the host chicks out of the nest.
So just on that basis there is not much option to target raptors. I don't know
if that is the complete reason. That is not to suggest that this has always
been the case through history or will remain so into the future. One rare
quoted example though is that the Channel-billed Cuckoo has been recorded to
parasitise the Collared Sparrowhawk. Size difference still applies. All other
examples I know of include passerines.
Philip
-----Original Message-----
From: Con Boekel
Sent: Friday, 28 December, 2018 12:23 PM
To: canberrabirds chatline
Subject: [canberrabirds] Why don't cuckoos...
Geoffrey's musings reminded me of a stray thought occasioned by the
larger than usual numbers of Koels lurking visually but not vocally in
Upper Turner this year.
One sighting involved several Koels and a Collared Sparrowhawk in the
same tree at the same time.
Here is my question: 'Why don't cuckoos parasitize raptores?'
regards
Con
*******************************************************************************************************
This is the email announcement and discussion list of the Canberra
Ornithologists Group.
Emails posted to the list that exceed 200 kB in size, including
attachments, will be rejected.
All emails distributed via the list are archived at
http://bioacoustics.cse.unsw.edu.au/archives/html/canberrabirds. It is a
condition of list membership that you agree to your contributions being
archived.
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 manager: David McDonald, email
<>
--
Message protected by MailGuard: e-mail anti-virus, anti-spam and
content filtering.http://www.mailguard.com.au/mg
Click here to report this message as spam:
https://console.mailguard.com.au/ras/1UN5Aykicz/4RUmKx32V7DXzs8GXxaFcR/-1
|
