Sheer genius of the long-distance flier
On THE island of Rum in Scotland, there is a mountain called Trollval: Old norse for the Hill of Trolls. It’s said the name comes from the norse seafarers who heard unearthly voices from underground, and concluded they were those of trolls.
actually the noise is Manx shearwaters, which in summer breed there in huge numbers, raising their single offspring each year in sandy burrows. They do make a lot of noise, it’s true, though I find it rather genial and bubbly, if a little screechy at times.
The Manxie is full of surprises — most of its life is spent far out at sea, and 90 per cent of it in total solitude, says MorganGrenville. For land-based social animals like ourselves, it sounds a lonely and desolate existence, but it is one for which the shearwater is supremely well-suited.
Their flight is a miracle of evolution, and their lives begin with a quite amazing feat. after 60 days of diligent feeding by its parents, perhaps on Rum, or on Skomer off the coast of Pembrokeshire, the fledgling bird will be abandoned.
after preening away its downy feathers, the young bird will stumble to the entrance of the burrow (elegant fliers are rarely elegant walkers as well), then flap its wings, rise up into the darkness . . . and from that moment on, says the author, may not touch land again for another three years, ceaselessly roaming the oceans, covering as much as 40,000 miles each year.
He gives us a striking bird’s-eye view of this journey, as the shearwater flies south, down past the Bay of Biscay and the dusty coast of Morocco to Senegal, and then, exploiting the atlantic weather systems first used by Portuguese sailors 500 years ago, catching ‘the helpful South atlantic gyre’ — or vortex — to whisk across to Brazil with little effort.
The bird will pass by ‘the low plains of Patagonia . . . the flaring gas outlets off Venezuela . . .’ then, using the atlantic’s clockwise gyre, sail up to the Caribbean, north to fog-bound newfoundland, and finally back across the north atlantic.
When it’s four years old or so, it will return home to mate — perhaps even to the very burrow it was born in, the entrance about the size of a side plate.
The navigational powers that make this possible are almost beyond our comprehension, but they involve ‘a mix of sun, stars, magnetic pull, homing instinct, sight, sound, smell and memory’. The
shearwater’s flight is a thing of aerodynamic beauty, honed by 120 million years of natural selection. Flying just a foot or two above the water ‘ as if attached and moulded to it’, they occasionally slice the surface with their wingtips.
They ride the subtlest updrafts and downdrafts, exploiting small differences in air pressure to soar and then dive with barely a wingflap, hour after tireless hour. One bird, carrying a tiny tracker, flew south with the trade winds at an average speed of 55kph (34mph), for an incredible 139 hours. Along with all the wonder of the bird itself, there’s some nice self-portraiture by the author. When younger he served eight years in the Royal Green Jackets, and he finds himself nostalgically looking forward to some hard tramping and wild camping in the wilds of Rum, as he had done in his Army days. Later, he becomes so fixated on shearwaters that he decides to follow them all the way down to the southern oceans, spending time in Argentina and out at sea, ‘a strange and impractical resolution’, he admits, for a man ‘who got seasick watching pirate films’.
Shearwater is sheer delight, a luminous portrait of a magical seabird which spans the watery globe with a wind-borne ease our roaring aeroplanes can only dream of.
The book is also tinged with shame over human behaviour towards the natural world. Two thirds of all seabirds have vanished since 1960. The same is true of insects. ‘If you extend the population line . . . you arrive into silence about 2060.’ For seabirds, for insects . . . for everything. This is only as far forwards as Mrs Thatcher becoming PM is back. For now, perhaps the relative prospering of our Manx shearwater numbers will just have to be our consolation.