As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Friday 15 June 2018

Parasitic Birds and Parasitized Host Birds

1 Jun 2018

English Translation: Asia Club, a WBSJ Volunteer Group (YOKOYAMA Kazuko, KASE Tomoko)

“In a quiet lakeside forest
The cuckoo is calling for you,
‘It’s time to wake up,
cuckoo, cuckoo, cuckoo, cuckoo, cuckoo, ,,,”

Most Japanese know the above song, which is sung over the melody of the worldwide popular nursery rhyme, “Incy Wincy Spider”.  I feel refreshed whenever I hum it in the morning, as it is really suitable for this pleasant season of May.  Four species of the cuckoo family come to Japan around the middle of May from South Asia, telling us that summer has come.  I would like to show you photos of three species of them, except Hodgson’s hawk-cuckoo, which I have never succeeded in photographing yet, and also introduce “Brood parasitism”, their unique breeding habit they have in common.

Brood parasitism is a habit of a bird, which does not make its own nest, lays eggs in other bird’s nest secretly and relies on the host bird to raise the chick.  To the host, the nest owner and the tentative parents to the chick, it is nothing but an annoying event.  The cuckoo family bird chooses a nest whose owner has just started laying eggs, takes away one egg of them and lays one of her own.   This egg hatches a little earlier than the other eggs of nest owner, and moreover the chick, with eyes still unopen and no feather developed yet, puts all the host’s eggs on its back and pushes them out, so that it exclusively occupies the whole nest.  Thus the chick thrives on the food its tentative parents carry for its now-dead “tentative siblings”, until it has grown much bigger that the host parents and then leaves the nest.

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