Swifts, swallows, and housemartins (Delichon urbica) never seem to stop their flight once they arrive at our shores in the spring. Today, there was a whole flock of housemartins gathering on overhead wires in Aldreth, Cambridgeshire, to preen and perhaps make their plans for the long and perillous return journey to sub-Saharan Africa. Their summer of breeding and feeding in the British Isles and the European mainland nearing an end.