I've not noted large aggregations of C-bCu's in the day but we did flush around
12 roosting together, while conducting nocturnal surveys out near Gunnedah NSW.
It was late in the evening, the tree was an isolated individual surrounded by
grassland and there were no fruiting trees nearby to my knowledge. The birds
were clearly roosting together not in response to a food source, which made the
observation very interesting to me. The time of year was late January (2011),
which suggested a post-breeding group likely made up of many young birds and
perhaps a few adults, unfortunately there was no way to tell, they disappeared
into the dark very quickly. I guess we have no way of knowing how many C-bCu
eegs are deposited in the nests of other birds throughout the breeding season,
could it be possible that the the 12 were a pair and their reunited progeny for
that year and/or previous years?? There have been rumours, but have we
established whether post-breeding groups are related i
n any way? if so, is it intentional or just likely due to the birds living and
then departing from the same general area???
I have watched C-bCu's luring Currawongs out of the nest, presumably to allow
the female an opportunity to parasitise the brood. The birds fly high around a
stand of trees where the Currawongs are nesting, calling loudly, and the
Currawongs just cannot resist to try and chase them off. Perhaps the
indiscriminate calling we hear by individuals or pairs is an endeavour to draw
other birds out to alert the C-bCu's of occupied breeding territories???
Other than that I think we might be able to assume that C-bCu's call for some
of the same reasons other birds call. We assume they don't establish
territories, but most birds defend breeding territories or food sources within
defined territorial bounds and it's likely that C-bCu's are carrying out
similar breeding season behaviour, albeit not tied to a personal nest site
(unless they view the nests of their surrogates as a resource worth defending).
Territory posturing may then explain the calling aggregations. Other cuckoos
appear to call as territorial proclamations: Koels are very competitive,
Fantailed, Horsefield's Bronze, Shining Bronze, Brush and Pallid are very vocal
and I recently noticed many a brawl amongst competing Pallids in the Goulburn
area (NSW sthn tablelands) this spring, induced and fueled by calling
individuals.
Certainly cuckoos are one of the easiest groups to attract by call, a suitable
whistle to Shining Bronze is the easiest way to get a closer view.
Allan Richardson
Morisset NSW
On 06/12/2011, at 5:36 PM, Laurie Knight wrote:
> Well there is that, but CBCs often call when they are on their own with no
> others in earshot. They call when they are high up and not being mobbed, and
> they call when they are flying in circles closer to the ground. I have never
> heard one call near a fruit tree.
>
> The thing is that a lone CBC calling would seem to be a more obvious target
> (given that it is calling attention to itself) particularly when it is flying
> high.
>
> I have heard CBCs make a bit of a chuckling call that might be similar to a
> raptor.
>
> Are there any published records of their behaviour when they are nest raiding?
>
> Regards, Laurie.
>
> PS I am not sure that it was a grammatical necessity to change the subject
> line. (I think that makes it a separate thread in the archives).
>
> On 06/12/2011, at 2:44 PM, Stephen Ambrose wrote:
>
>> I think it is more likely to ensure "safety in numbers" especially while in
>> flight. A lone individual is more likely to be mobbed by a nest host species
>> (currawong or magpie) or preyed upon by a predator (large raptor) than one
>> that is part of a flock. An individual calling as it takes flight alerts
>> others to follow. Calling while in flight keeps individuals within a flock
>> close together, especially if they are flying at night.
>>
>> Dr Stephen Ambrose
>> Ryde NSW
>>
>>
>> -----Original Message-----
>> From:
>> On Behalf Of Philip Veerman
>> Sent: Tuesday, 6 December 2011 2:56 PM
>> To: 'Birding Aus'
>> Subject: [Birding-Aus] What is the function of Channel-billed Cuckoo's
>> calling flights?
>>
>> Interesting question. Presumably, like most migrant cuckoos they call for
>> social or sexual reasons when they arrive at their breeding areas. But I
>> don't think that is the question being asked. Which raises to me the idea
>> that yes they are cuckoos, but in their way of feeding they are different
>> from most cuckoos. They are mainly fruit eaters. I would think that fruit is
>> a geographically concentrated food source, as distinct from the more evenly
>> spread insect food source that most cuckoos use. So I propose (for
>> consideration, with no proof I hope you understand) that maybe it is the
>> calling related to finding food - if they want to share it that is, or maybe
>> it provides a way to assemble in groups at places with abundant food.
>>
>> Philip
>>
>>
>> -----Original Message-----From:
>> On Behalf Of Peter Shute
>> Sent: Tuesday, 6 December 2011 8:29 AM To: 'Greg & Val Clancy'; 'Laurie
>> Knight'; 'Birding Aus' Subject: Re: [Birding-Aus] What is the function
>> of
>> Channel-billedCuckoo callingflights?
>>
>>
>> What's the most CBCs you could expect to see in a flock? Do any other cuckoo
>> species fly in flocks like that?
>>
>> Peter Shute
>>
>>> -----Original Message-----> From: >
>> On Behalf Of
>>> Greg & Val Clancy > Sent: Tuesday, 6 December 2011 7:41 AM >
>> To: Laurie Knight; Birding Aus
>>> Subject: Re: [Birding-Aus] What is the function of Channel-billed Cuckoo
>> callingflights?
>>>
>>> As they call at all times of the breeding cycle I would think
>>> that the
>>> suggestion that it is to 'pick up' immature birds would not
>>> fully explain
>>> why they call in flight.
>>>
>>> Regards
>>>
>>> Greg
>>> Dr Greg. P. Clancy
>>> Ecologist and Wildlife Guide
>>> Coutts Crossing
>>> NSW
>>>
>>>
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