Migration Hotspots, by Tim Harris – review

Consider for a moment the plight of the willow warbler. Russian birds of this species fly between eastern Siberia and southern Africa and back every year of their short lives, a distance of nearly 7,500 miles in each direction. Each weighs roughly as little as two teaspoons-full of sugar.

But at least these tiny birds can refuel on their journey. Southern bar-tailed godwits are unluckier. These fly the 7,000 or so miles between New Zealand and Alaska over the immense Pacific Ocean — hence non-stop — twice each year. Moreover, Arctic terns migrate from the Antarctic to the Arctic and back again: a fledgling of this species, born on the Farne islands off the Northumberland coast, was recorded only three months later near Melbourne, Australia. And some shear-water have been tracked flying up to 46,000 miles per year, so that a 30-year-old bird could have flown the equivalent of 50 circuits around planet Earth.

Small wonder, perhaps, that the novelist-cum-moral philosopher Dame Iris Murdoch declared such migratory arrangements in a 1982 lecture (with comical seriousness) ‘wasteful and immoral’ and, moreover, ‘convincing evidence of the non-existence of God’. It is thought that 2 billion passerines, 2.5 million wildfowl, 2 million raptors and millions of waders migrate from Eurasia all around the Arctic to winter in Africa.

Hunger and exhaustion are not the only perils such birds face. I once saw black-necked cranes sailing over the Himalayas at great altitudes from Tibet into Bhutan; and whooper swans have been observed at nearly 27,000 feet where the air temperature is minus 40 degrees C. Hunters in north-east India net, kill and skin an estimated 120,000 to 140,000 migrant birds every year for food; while some Mediterranean countries carry out similar annual carnage, not to fill empty stomachs but in the name of ‘sport’.