The amazing migration of swallows

By Charlotte Owen

WildCall Officer 

For many of our seasonal visitors, the change in the weather that comes in September/October means it’s time for them to go.

Groups of swallows gather along the coast from September to swoop across the sand at low tide, scything through clouds of early morning midges for a protein-packed breakfast. They would already have been moving steadily southwards and then make a final pit-stop on the shore before heading out to sea to begin a six-week flight to South Africa. Most migratory birds will fatten up significantly before embarking on a long-distance flight, but swallows don’t need to, since they will catch plenty of mosquitoes, gnats and other in-flight snacks on the wing. Still, it makes sense to fuel up while they can as they wait restlessly at the shoreline for the optimal weather conditions that will signal their departure. Swallows travel by mainly by daylight and if dawn breaks with clear skies and a tailwind they will set off shortly after sunrise to cover up to 200 miles in a single day. They stop to rest overnight, often in huge flocks that will roost in reedbeds and other sheltered spots along the way.

The exact migration route varies depending on their departure location but ‘our’ swallows cross the Channel to fly south through western France and eastern Spain before making another sea crossing to reach Morocco. Then they must fly over the endless dunes of the Sahara, the largest hot desert in the world. This hazardous stretch will be completed in one go, since there aren’t any handy stopovers, and it’s the only leg of the journey undertaken after dark, during the relative cool of the desert night. By November, swallows will be flying through the tropical humidity of the vast Congo rainforest before finally reaching the winter warmth of South Africa and Namibia by December. The entire flight is some 6,000 miles in total, which is an incredible feat for a bird small enough to fit into your pocket.