Hi All,
An interesting thread. Over the prevoius two summers (but not this one, for
some reason) we had a pair of CBCs that appeared to maintain a territory in our
street. Whilst they were particularly active/vocal in the early morning and
evening we heard them at odd intervals throughout each day.
I find Allan's observations of multple birds roosting together particularly
interesting. Early on in their stay, our CBCs had the expected interactions
with the local Torresian Crows to get the female into the nest. However, they
were here for at least a couple of months after that, keeping up with their
aerial calling throughout that time. As we live in an area without an obvious
source of fruiting trees, it got me thinking: were they maintaining a territory
around their nesting sites with the aim of 'picking up' their young once they
had fledged??
Regards
Judith
> From:
> To:
> Date: Wed, 7 Dec 2011 08:00:17 +1100
> CC:
> Subject: Re: [Birding-Aus] What is the function of Channel-billed Cuckoo's
> calling flights?
>
> I like Allan's hypothesis of CBCs calling or creating a commotion while in a
> forest or woodland as a diversionary tactic to allow a female to sneak in
> and parasitise a nest. This certainly makes sense to me.
>
> Stephen Ambrose
> Ryde NSW
>
>
> -----Original Message-----
> From:
> On Behalf Of Allan
> Richardson
> Sent: Tuesday, 6 December 2011 7:59 PM
> To: Laurie Knight
> Cc: Birding Aus
> Subject: Re: [Birding-Aus] What is the function of Channel-billed Cuckoo's
> calling flights?
>
> 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
>
>
>
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