Screaming from the rooftops

A sky filled with shrieking, swooping swifts is one of the true delights of summer. But it is one we need to work hard to protect

- DAVID TOMLINSON

NO bird symbolises high summer more than the swift: the flocks that race like hooligans through our towns and villages on July evenings, screaming ecstatically, capture the very essence of the season. Once known as devil birds, swifts have always been creatures of mystery, appearing suddenly in early May and departing equally abruptly in August. Nobody knew where they came from nor where they went to. The naturalist Gilbert White thought that they hibernated, but Edward Jenner (1749-1823), the man who invented vaccination, was the first to suggest that they migrated.

Jenner marked several swifts by capturing them at their nests and cutting out their toes; he discovered that his marked bird returned to the same nest sites in subsequent years. However, his most compelling argument for migration was the fact that the swifts he examined in May were fat and in excellent condition, which wouldn’t have been the case if they had spent the winter in a state of torpor. But although Jenner had deduced that swifts migrated, the mystery of where they disappeared to remained. Africa seemed to be the destination and this was corroborated by an observation made by Dr. David Livingstone, who reported seeing a flock of 4,000 over the plains of Kuruman in the Northern Cape of South Africa. Africa has a number of species of similar-looking swifts that are challenging to identify, so Livingstone’s observation may not have been of Apus apus, the common swift, but possibly