OUT OF STEP

Embarking on long and exhausting journeys over land and sea, migrating birds are on the front line of climate change. How are they faring in a world of shifting weather patterns?

- JOE SHUTE

IN THE LATE SPRING OF 2020, people across Britain started to notice a strange absence from the skies. Swallows, those harbingers of summer that are steeped in centuries of folklore, were nowhere to be seen. Birdwatchers from the east coast to Cornwall, from the Midlands to the south coast, were all reporting a dearth of the migratory bird from Sub-Saharan Africa.

The curious case of the missing swallows, which usually arrive in Britain to breed each spring, was eventually solved. The culprit? The weather. On the night of 5th April that year, a storm had whipped up over the Aegean Sea around Greece, just as flocks of swallows (and swifts) were migrating north. Southerly winds pushed them into Aegean air currents that proved too powerful for many of the already exhausted birds. Over subsequent days, thousands of dead swallows littered the streets and balconies of Athens.

Such extreme weather events are becoming more frequent as a result of climate change. And the way in which our weather is changing overall is thought to be having a dramatic effect on migratory bird populations. Climate change is sending nature and humans into a state of flux.

Studies have found that swallows are now arriving in the UK a fortnight earlier than in the 1960s, and breeding a full 11 days earlier (in autumn, the birds are also departing back for Africa later). In recent years, swallows have been spotted by English county recorders as early as February, while there have even been numerous reports of the birds overwintering in the south of England. The old saying that ‘one swallow does not make a summer’ has rarely seemed more apt. The warming climate is changing what we presumed to be fundamental seasonal rhythms.