Written on: 28. 9. 2011 in the category: news Uncategorized

I just don’t accept the Darwinian law of natural selection as a means of explaining migration

ON Monday evening, the swallows gathered on the telephone wires. By Tuesday, they were gone, prompting some pretty age-old questions, such as: what will they do when underground optical-fibres and iPhones make telephone wires extinct? Will the swallows dig pits to squat subterraneanly on the fibres? Or will they cluster on children’s mobile phones, as the weighty little dears stand outside their schools, ponderously gorging upon a few thousand calories until their mothers drive them home, a massive mile away?

Never fear: the swallows will find a way. They always do. They left about a week earlier this year than last, after a magnificent breeding summer. I recorded the arrival of them and their cousins, the housemartins, beneath our eaves, in April: both species were more numerous than in any of the thirteen previous springs we have been here.

The summer might have been poor, but the swallows and martins that it brought us did not disappoint. All the promises of spring were fulfilled: by late August, scores, and maybe hundreds of birds were wheeling and spiralling in the evening skies about us, feasting on a banquet of midges.

An entomologist once told me of how he had dissected the corpses of swallows, martins and swifts, and found that each bird takes subtly different kinds of prey.

The tiny flying insects they catch are almost invisible to us, and besides being small, they are constantly moving, sweeping the air for the molecular granules shed from pollen.

Yet those spiralling swooping birds, moving through three dimensions at anything between 25 to 40mph, can nonetheless, in an instant, assess, capture and consume the right kind of midge, or avoid it entirely.

It is a beautiful thought: all the hardwiring in the bird that makes this astounding feat possible — and in a brain that is smaller than a match head, and which also controls the circuitry that tells a housemartin how to collect mud and water and feathers and grass to make a nest hanging on a vertical wall, unsupported by anything other than its own beak-made cement.

The same brain will know how to feed and raise young, and now, as you read this, to navigate over the Sahara, to the spring grasslands of southern Africa. Yet it is not just hard-wiring, nor is it simply predictive.

A reader in Spain reported that local swallows had departed fully two weeks ago. Yet some swallows in Spain in recent years have chosen to winter there. They chose — which is the word I use, for want of any other. Can the decision have been a simple binary-trigger activated by warmer autumn weather? But some did not go: maybe they didn’t have the trigger. Or maybe they did, and ignored it. Ah, you see: questions, questions.

I had the great pleasure of talking to Richard Dawkins at Listowel Writers’ Week in the summer. He effortlessly batted all my questions to the boundary, save two: one was the origin of life. He didn’t know it: and that was fair enough, it all being so long ago.

The other was about migration. I just don’t accept the simple Darwinian explanation of natural selection as a means of explaining migration. You cannot breed if you’re dead, and failed migrations over oceans mean certain death. We know this, from man’s own migrations, and from RAF bombers in the Second World War, which even with navigational equipment, could miss entire cities by hundreds of miles. That was the question he didn’t answer, because I didn’t ask it.

Looking for my car keys the next morning, I found the unseen cue card with the question on it in my pocket. Which is the way of error: without the right hardware when and where you need it, you will probably fail — yet how do you acquire that hardware in the first place?

After all, I chose to have the card, albeit unsuccessfully; but what about the very first migrating swallow? Ah, you see: questions, questions.

AND so few answers that are pleasing. Migration must surely be one of the costliest survival mechanisms that nature has devised. Maybe half of all the swallows flying for the first time to Africa this week will be dead by Sunday. Five billion birds will this autumn head from Europe to Africa. Awaiting them at around one thousand feet over the Mediterranean are hunting-packs of male Eleonora’s Hawk: they alone will kill ten million migrants. Uncountable numbers of others are trapped in manmade nets all around the Mediterranean littoral, for what are to us delightful migrating songbirds, to the locals are merely stamped and addressed airborne protein.

When I wrote a column on swallows this time last year, I did not remotely begin to guess that a winter of shocking harshness would begin in November, and would last until April. Our hedgerows are now brilliantly scarlet with haws and hips, which some account an omen — but I rather doubt if it is in nature’s nature to bestow such premonitory providence.

Either way, Met Eireann forecasts a final burst of summer this weekend: but then the long night of winter’s bleakness finally begins. Prepare.