Courting birds spread spring wings

Damien Enright says sunshine brings out best in nature.

A BEAUTIFUL few days in mid-February and, just as there’s so much to look at and admire again in Ireland, we’re heading for La Gomera in the Canary Islands on Valentine’s Day.

During the dreary weeks since Christmas I’ve many a time yearned for a bit of sun to bring some colour back into the world, and now that we’re off the islands of almost eternal sunshine, the sun visits here! But, much as I regret missing these days of transformation in west Cork, spring will have reached La Gomera too, with the flowers bursting forth everywhere, the terraces of the huge volcanic valley greening by the day, and the sea warm enough to swim in.

But how lovely does our own native land appear on these recent sunny mornings! The field we look out over at breakfast is silver with dew, and the leaves of the few spindly holly bushes, between us and it, shine like small mirrors.

This morning, when I was out walking, the sun was so warm I had to take my coat off and, to save carrying it, stash it under a bush. The surface of the bay was as still as mirror glass, the boats set in it like toys. Big sand bars divided the channels, acres of sand white as tropical atolls. Far away on one of these peninsulas a man walked with his dog. He reached the tip where the incoming tide broke over it and, for a minute, I thought he’d better beat a quick retreat before the sea came in around him, but he had plenty of time. Beyond the tip of the sand spit, beyond the shelter of the woods and the headland, the sea was piling in, in long, low, inexorable waves, one behind the other with hardly a break between. The prows of the boats in the channel by the pier had swung and now pointed seaward, facing the incoming tide. Out on the headland the sea stretched blue to the horizon, under a sky of blue without a cloud.

It’s extraordinary how a few warm days can bring the hedgerow world to life and put a buzz back in the air. Glittering hover flies drift and hang over the new buds of the Alexanders, the tall, celery-like plants with green heads made up of hundreds of tiny flowerlets. Moths arrive in the house at night. In the garden there are now two robins; clearly, our resident robin’s singing has attracted a mate into the territory, and all the bonding and dining together at the bird table now commences.

In the case of birds, spring will bring extraordinary physiological changes. I cannot imagine what would happen if human beings underwent the same. As days lengthen the hormones in birds have an increasing effect, not only on the bird’s libidos but on their reproductive gear.

Outside of the breeding season, these are superfluous to requirements, and shrivel almost to invisibility. But, come the spring, male testes grow up to 300 times larger and female ovaries swell up to a 1,000 times their size. The change is gradual, and the organs become functional for different species at different times. Until they are fully restored no offspring can be engendered.

The pairing and courtships start early and now are already well under way. For species that mate for life — ravens, woodpigeons, house sparrows — the attachments are already formed, and the stress of forming a bond between birds that have never before met is obviated; it’s just an amorous reassertion of a relationship already long established.

For species where the sexes separate in winter, but live close to one another — like back-garden blackbirds, tits, chaffinches and robins — there’s already familiarity, but a testy getting-to-know-one-another-again period is required before they begin to preen and snuggle up to one another.

Then there are the birds that form no bonds from year-to-year, but meet when foraging together in winter flocks. Siskins from Scandinavia that met in Ireland or Britain in winter may pair-bond here and fly together to Norway or Sweden to breed. There are also the many ‘lonely hearts’ birds that enter the breeding season with no mate, and spend all February and March advertising, singing and assessing the results. If they’re not successful in finding a partner, they’ll try moving to other territory and readjusting the delivery, the image or the song.