Home

Happy Returns

The Homing Instinct: The Story and Science of Migration
By Bernd Heinrich (William Collins 352pp £16.99)

Many years ago my mother sent me a postcard, its text beginning: 'We're going to Bali tomorrow and it's all absolutely ghastly.' It would be hard to nail one of the central contradictions of human and animal life more succinctly: the visceral tug of home that coexists with the eternal lust for wandering and adventure. Both are essential survival instincts.

The greatest journey of a lifetime is neither complete nor satisfactory until you have returned home: homecoming is what gives the journey its meaning; if you don't believe me, ask Odysseus and Leopold Bloom. And yet home is also something to leave - 'what is a woman that you forsake her,/And the hearth-fire and the home-acre' - if not with joy, then at least, like Dr Watson, with the thrill of adventure in your heart.

I have long been familiar with the fact that whenever you try to draw hard and fast barriers between humans and our fellow animals you find them dissolving and melting away: we are forever identifying continuities where people once boasted about uniqueness. You can find evidence of language all over the animal kingdom, including among honeybees, for what is the waggle dance if not an exercise in conceptual communication?

You find an apparent understanding of death in elephants, altruism to unrelated conspecifics in vampire bats, creative musicianship in nightingales, visual artistry in bowerbirds, tool-making in many species, problem-solving in crows and cultural transmission in species without number. In the same way, we find a thousand instances of our own kinship with the rest of the animal kingdom every day.

So it is hardly surprising that home is another of those big ideas that burst beyond the boundaries of species, class and phylum. Honeybees must go out and forage, but none of that's any good if they can't find their way back to the hive again. 'Hive and home' is rather more than a precise geographical location: it's the entire meaning of a bee's existence.

Bernd Heinrich works his way through the jungle of ideas that arise from the universality of the concept of home, never for a moment abandoning the principle that God dwells in the details. He finds himself fairly staggered by, for example, the migration of the bar-tailed godwit, a chunky wading bird familiar enough in Britain. These birds make an annual journey from Alaska to Australia, which would be astonishing enough if that were all. But the fact is that they do the whole damn journey in a single flight. A female fitted with a transmitter flew 11,680 kilometres in just over eight days. When they touch down at last, they have lost half their bodyweight. Heinrich is not the sort of scientist to go off on one, but the godwits, it seems, give him no choice.

'I may be anthropomorphizing to suggest the godwits have a "love" of home, but although we can never know what they feel, it is hard to deny that they do feel.' No doubt as they set off for lands on the far side of world they are afflicted with a terrible restlessness, a feeling of discontent with the place where they are, and perhaps for those birds who have made the journey before there is an ache for distant familiar lands, the avian equivalent of wondering if the church clock still stands at ten to three and whether or not there is honey - well, worms in the case of a godwit - still for tea.

I was particularly struck by the species that may not have a physical home but instead its equivalent in gatherings of their conspecifics: home is where the herd is. Sometimes members of a species gather in the sorts of numbers more familiar to astronomers than to biologists. I have visited a breeding site of the red-billed quelea in Zambia, and looking for nests was like looking for stars at dusk on a frosty night.

Heinrich lists five North American species renowned for congregating in mind-baffling numbers: the Rocky Mountain grasshopper, the passenger pigeon, the Eskimo curlew, the Carolina parakeet and the bison. Four of these are now extinct and the fifth, the bison, hangs on as a shadow of its former self in protected areas.

It is also true that the way of the long-distance migrant gets harder and harder in the modern world. There have been measured declines in many of our own British spring and summer favourites. Most people in Britain now go through the year without hearing a cuckoo; as a boy I used to hear them on Streatham Common. Turtle doves have made the terrible transition from common to special. This book is at least in part a celebration of wonders we are in the course of losing.

Heinrich displays the caution of the scientist - probably cultural rather than innate - and this may irritate those with a taste for irresponsible speculation, but there is poetry in the accumulation of example and detail. The work of the experimenter is wonderful and at times engagingly mad: would you have thought of fitting turtles with glasses to find out the secrets of their navigation techniques?

What emerges from The Homing Instinct, a book richer in research than in high-flown phrases, is a sense of the way that home matters. It matters to locusts and pigeons just as much as it matters to you and me. Home has a powerful centrifugal force, flinging us away from its comforts into a wild and challenging world, and it also exerts a still more powerful tug, drawing us back again with just a twitch upon the thread.

When Pooh and Piglet were lost in the forest, Pooh was able to find his way home because, when all was still and quiet, he could hear the voices of his honeypots calling to him across the trackless wastes of Hundred Acre Wood. So it is for honeybees and humans, so it is for us all. Home is part of who and what we are.