Dear Birders,
While observing in the Chiltern National Park (north-east Victoria) on the
6/4/97 with the Ovens and Murray Bird Observers, I encountered a
perplexing identification problem involving a Cacomantis sp. cuckoo. It
seemed to be somewhat of an intermiediate between a Brush and Fan-tailed
Cuckoo.
It was the size of a Brush Cuckoo (around 23cm), lacked the yellow-eye
ring of a Fan-tailed Cuckoo and had a greyish-head and breast. The breast
colour eventually graduated into buff, that was the darkest around the
bird's vent and belly. The upperparts were a light grey-brown. All these
features are in opposition the the diagnostic features of a Fan-tailed
Cuckoo.
However the bird's tail was very much like a Fan-tailed Cuckoo. It was
more rounded and longer than a Brush Cuckoo and had whitish-buff notches
along the sides. The bird was very much like a Brush Cuckoo in all
respects except for this. It lacked the light-chestnut breast and
blue-grey upperparts of the Fan-tailed Cuckoo. It did not call at all.
It could be possible that this bird is a Brush Cuckoo that has not yet
moulted out its juvenile/immature tail feathers and so is still retaining
the whitish-buff notches present on this. It could also be likely that it
could be an abberant Fan-tailed Cuckoo, lighter in plumage than usual or
in a transition immature/adult plumage stage.
In terms of distribution and habitat it is more likely that the
Fan-tailed Cuckoo would be present in Chiltern National Park (being a
box-ironbark forest) than Brush Cuckoo. However the Brush Cuckoo has been
recorded in the forest before and it is also likely that it may have
dispersed into a more open habitat after spring/summer breeding or is on
migration. I have observed this species at Freeburgh (100km south, wet
forest) so it's quite possible to see it here.
The bird was noticed perching in a Cherry Ballart 10-15 metres away and
was mobbed a female Scarlet Robin and Honeyeaters. It was observed by five
observers including myself who did not arrive at a conclusion on the
identifiaction as well.
Cuckoos in general seem to pose many identification probelms in terms of
juvenile/immature/adult plumages and between species. Any help on this
matter would be very much appreciated.
Best Regards,
Michael Ramsey
Bundoora, Vic
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