Friday 22 September 2017

Time of the essence for cuckoo

THE cuckoo's short time on this island is rapidly ending after weeks of climate confusion. Just what do such migrant birds, for whom time is of the essence, make of it all, you may well wonder?

Do they accomplish what nature has programmed them for in their 12 weeks or so allotted span with us?

An old country rhyme, which I heard again from a sheep farmer in Leitrim the other day, goes:

"In April I open my bill/ In May I sing all day (night and day)/ In June I change my tune/ In July I fly away.''

Sheep and lambs were having their own grazing concerns as, on one clear morning, one cuculus canorus flew overhead like a sparrowhawk, on long grey wings, singing as it went, hoping for a last throw of the dice as martins skimmed the snipe grass, gobbling insects after rain like hoovers out of control.

The singing male cuckoo's business had been to find a mate, not an easy task as the species of host birds in whose nests the cuckoo eggs are laid have been nesting earlier and have been in decline also.

Numbers of meadow pipits, robins, dunnocks and pied wagtail populations have been falling and cuckoos cannot suddenly switch nest-searching to other species as their eggs are genetically programmed to resemble those of birds they normally target. Confusion reigns!

Historically, the poor cuckoo has not evoked much sympathy. The bird's parasitical image goes back a long time. The Roman naturalist Pliny claimed the weaned cuckoo eventually ate its foster parent, while Chaucer, in his Parliament of Fowles, simply called the bird a murderer!

In King Lear, Shakespeare had the Fool say: "The hedge sparrow fed the cuckoo so long that it's had its head bit off by its young.''

Certainly, as its natural mother had promptly removed an egg to make room for one of her own, on hatching, the rapidly-growing usurper pushes overboard the remaining eggs and nestlings competing for food delivered by the unsuspecting parent birds.

The female cuckoo is a very fast mover. Having poked out an egg from a host nest, she promptly squirts in a replacement -- in 10 seconds -- while clinging to the nest rim, repeating this on a daily basis up to 15 times, suitable nests being located.

Cuckoo numbers arriving here each year are estimated at between 3,000 and 6,000 but are in decline. The birds appear to be remarkably heartless breeding machines in that, having mated and quickly laying eggs, they clear off back to Africa, leaving their young to follow during July and August in a behaviour pattern "demonstrating the remarkable quality of innate navigational instincts'', as the naturalist David Cabot puts it.

Cuckoos do their bit for the farmer while here, eating hairy caterpillars that other birds find poisonous, digesting them because of a protective stomach lining which renews itself.

The pitch of the distinctive call notes are D and B or D and B-Flat, treble stave. Beethoven, when introducing the cuckoo sound at the end of the Second Movement of the Pastoral Symphony, gives the two notes D and B-Flat. So I learn. It's an uplifting sound on the morning air.

Sunday Independent

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