Mark
I have been sleeping in a tent in Turner (not homeless - overflow from
extended families visiting for Xmas!) and can attest that Koels are
calling well past dusk and well before dawn. But not in the small hours.
I can't recall hearing the 'koh ell' call at all this season.
regards
Con
On 12/28/2018 5:20 PM, Mark Clayton wrote:
> I won't get into the nesting of Koels and raptors but something that I
> have noticed this year if that the male koel(s) in Kaleen are NOT
> giving their typical, usual "coo-ee (or koel) call. I have only heard
> it twice this season and then only very early when they first arrived.
> Both sexes are giving their other regular calls, and a lot of funny
> calls that I have not heard before. They are also NOT calling in the
> middle of the night.
>
> Anyone else finding this? The birds were somewhat late in arriving in
> Kaleen this year.
>
> Mark
>
> On 28/12/2018 4:55 pm, Philip Veerman wrote:
>> Hi Con,
>>
>> As for the Channel-billed Cuckoo, its usual hosts are corvids and
>> currawongs, so along with the Collared Sparrowhawk shows the meat
>> eating is not a problem, even though the adults mostly eat fruit (and
>> some meat). As for the Koel, there is no raptor small enough.
>>
>> Here is that "quite a few" again. Let's suggest that means 5 raptors
>> that are smaller: Collared Sparrowhawk, two small kite species and
>> kestrel & hobby. I also suggest that most raptors have a far more
>> aggressive and dangerous nest defence than most passerines. Your last
>> suggestion seems as good an additional reason as any. Or a variant is
>> that there are not enough raptors to go around to maintain
>> raptor-specific cuckoos. Either option would be hard to prove. Just
>> because there is not such a situation now does not mean it could
>> never happen or did never happen. Not all possibilities exist, at any
>> one time. Which is what I was hinting at before. Maybe over past
>> millions of years they have tried and been unsuccessful...... Who
>> would know?
>>
>> You might also like to check out this variant:
>> https://www.treehugger.com/natural-sciences/cuckoos-and-crows-teach-us-how-parasites-can-be-good.html
>>
>> Philip
>>
>> -----Original Message-----
>> From: Con Boekel
>> Sent: Friday, 28 December, 2018 4:21 PM
>> To:
>> Subject: Re: [canberrabirds] Why don't cuckoos...
>>
>> I don't know the answer but the question intriques:
>>
>> In terms of size. the Channel-billed Cuckoo is larger than quite a few
>> Australian raptores.
>>
>> In terms of diet, why not a meat-eating cuckoo?
>>
>> In terms of raptors predating/killing the cuckoo, current species of
>> cuckoos routinely evade/avoid their hosts, why not evolve to be able to
>> evade/avoid raptors?
>>
>> One possibility is that raptors are the highest trophic level and there
>> is not enough energy to go around to maintain raptors AND
>> raptor-specific cuckoos.
>>
>> regards
>>
>> Con
>>
>>
>>
>> On 12/28/2018 1:56 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
>>>
>>>
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