DECLINING populations of four more species of birds, including the once ubiquitous house sparrow, are causing alarm amongst scientists, according to the latest figures issued by the British Trust for Ornithology.
Along with the sparrow - whose numbers have suffered a massive drop in recent years - the others in decline are the much-loved barn owl, the fisherman's friend the pied wagtail, and the white ear, which winters in Africa but raises its young in Britain during the summer.
BTO scientists have been monitoring the size of the broods produced by these birds at nesting time - and found some alarming declines in the number of chicks hatching or reaching maturity.
Whilst more research is needed to establish precisely why this is happening, the ornithologists suspect that a shortage of insects available to feed fledgling sparrows could be to blame.
The slump on barn owl chicks may also be food related: recent widespread flooding is believed to have killed millions of voles and mice in the countryside, a vital source of food for growing owl chicks.