Saturday, 2 November 2013

A cuckoo in the garden


An unmistakable birdcall alerted me to the presence of a cuckoo in our garden this morning. The call was a series of ascending notes, sometimes described as semi-tones, indeed this bird has been called the Semitone-bird or Scale-bird. The bird calling in our garden was of course a Pallid Cuckoo.
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The adult male Pallid Cuckoo calling in the garden today. I have interrupted his calling.
Satisfied I am no threat he resumes his scales.
His energies were not completely focused on attracting a mate. He stopped calling to swoop down and grab a moth and then he moved to another tree to beat the moth a few time on a branch before swallowing it. Hairy caterpillars, grasshoppers, beetles and other insects make up the diet of Pallid Cuckoos.
The moth consumed he resumes calling.
The call, repeated over and over again, was coming from a male Pallid Cuckoo, a male because only the male makes the ascending call. The female, if and when she replies, only issues a single harsh note. Another name for this cuckoo is the Brainfever-bird, as it sometimes continues calling for long periods, including occasionally at night, which can drive some people mad, or at least it can become seriously annoying, especially if it is keeping you awake at night.
Another apt name for this species is Harbinger-of-Spring as it is a strong seasonal migrant to southeastern Australia where its return each Spring is announced loud and clear by the call.
The name cuckoo, applied to some 12 cuckoo species in Australia, derived from the cuckoo found in Europe, which makes a call sounding like “cuckoo”.  It is one of those onomatopoeic words where the sound of the word imitates the sound of the thing or action being described, as for example in the words hiss, buzz and bang.  In the case of the European Cuckoo the bird’s call is the sound “cuckoo”.  However in spite of bearing the name cuckoo not one Australian species makes a call that sounds anything like “cuckoo”.
Most Australian cuckoos, but not all, are nest parasites meaning they lay their eggs in the nest of another species leaving the unwitting hosts to raise their young. The Pallid Cuckoo is a “nest parasite” and some 50 species are potential hosts for Pallid Cuckoos with Yellow-faced Honeyeater being one of the most common victims, which is possibly not surprising given the Yellow-faced Honeyeater is also a strong seasonal migrant returning to southeastern Australia every Spring in large numbers to breed. 
Yellow-faced Honeyeaters are a common victim of the Pallid Cuckoo's nest parasitism. This bird has been having a bath.
The male Pallid Cuckoo is a grey bird with some brown hints. The female is a mottled rufous brown, a colour not needed for sitting camouflaged on a nest but very handy for sneaking in undetected to lay one egg in the nest of an unsuspecting pair of host birds while they are distracted by her mate. She removes one egg so the owners of the nest will not notice any change. When hatched the young cuckoo will eject the other eggs or hatchlings from the nest leaving only the cuckoo for the hosts to raise.
The male Pallid Cuckoo.
This is a juvenile or young male - note spots on wing covert margins. This photo was taken in Sturt National Park NW NSW.
The female Pallid Cuckoo - note the mottled brown and rufous colour. Photo taken on Wangarabell Road north of Genoa far East Gippsland.
The challenges of reproduction have seen many different methods evolved across various species to bring forth the next generation, however nest parasitism is one of the more fascinating solutions. 
The male Pallid Cuckoo called on and off in and around the garden throughout the day. I listened to see if a female answered his call. Just on dusk he was still calling when I heard a female respond with her one coarse note. Perhaps he did not call all day in vain?

2 comments:

  1. An interesting post. I wonder how cuckoos developed parasitism in evolutionary terms. I saw a program several years ago where researchers had found that the female European cuckoo retains eggs inside her longer than other birds so that the young one hatches in a shorter time and is larger than the host nestlings and thus able to push it/them out of the nest when it hatches. I haven't heard if ours are like that though.

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    1. Thanks for comments The Happy Wanderer. No doubt many before us have wondered how the Cuckoo's nest parasitism came about. Not sure how far back in evolutionary terms this development took place in birds however I notice that all of the cuckoo species I have seen have a strong resemblance which probably indicates nest parasitism has only developed once in one species and then branched into more species down the years. I must admit that I am no authority on the subject and for all I know other non cuckoo species may also be nest parasites? One species in Australia, the Pheasant Coucal builds a nest and raises its own young - there are always exceptions to the rule! I notice in Morcombe that the incubation time for the Pallid Cuckoo is 12-14 days which is shorter than the host birds and the egg is larger so the chick is larger than the host bird's chicks. Perhaps, as you say, the incubation time is shorter because the female Pallid C holds back laying the egg to allow for some development of the chick before laying. This would make up for the head start the host bird's eggs have as the Pallid must lay her egg into a nest with eggs.

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