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. |
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?
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.
ReplyDeleteThanks 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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