Swallow, swift and house martin populations have nearly halved, finds UK bird survey

Reduction in insect numbers contributes to drop, and there are declines across more than a third of bird species surveyed

Swallows, swifts and house martins were once a common sight over UK towns and cities, dextrously catching insects on the wing. But these spring and summer visitors are becoming increasingly rare, according to the definitive survey of the country's birds.

Populations of these insect-eating birds have dropped by 40% or more in the past decade, according to the latest Breeding Bird Survey (BBS) report.