Swallows staying put for winter as climate heats up
One December day in 1912, a farmer living in the former Natal province in South Africa made a discovery that changed the way we look at birds. It concerned a swallow, and a small metal ring placed around its foot.
The bird had been ringed 18 months earlier by a solicitor and amateur naturalist called John Masefield at Cheadle, Staffs. Subsequently it had flown thousands of miles, chasing the sun all the way to sub-saharan Africa.
For centuries we have celebrated the return of the swallows each spring, but no one had much of a clue where they went in the interim. In the 18th century, it was commonly believed the birds either hibernated underwater in ponds or disappeared into chimney pots to see out the winter.
Even avian experts could not quite comprehend how a bird not much bigger than a matchbox could undertake such an immense annual journey of around 6,000 miles.
But a study by the British Trust for Ornithology (BTO) has confirmed that in some ways the popular beliefs of previous centuries do indeed have a ring of truth to them. For increasingly, owing to our warmer winters caused by a changing climate, the birds are staying put all year round.
According to this year’s BTO Birdtrack survey, there have been almost 100 reports of around 12 individual swallows between Jan 1 and Feb 1, in the South and South West. Prof James Pearce-higgins, the BTO’S director of science, said even one such sighting a few decades ago would have been “unthinkable”.
It has been a mild winter: February ended up 1.5C (34.7F) above the longterm average while December was up 1.1C (34F). January may have been a wash-out, but it also stayed warm.
One swallow does not a summer make, as the old saying goes, but a dozen certainly shows us how our winter is changing.