In some areas of high squirrel density, more than 93 per cent of small birds? nests are predated. When combined with sparrowhawk activity it can result in 100 per cent breeding failure and a loss of 85 per cent of adult birds.? These are the alarming figures to emerge from research carried out by Professor Roy Brown of Birkbeck, University of London, who has been heading a review for the wildlife charity Songbird Survival into the decline of UK songbird populations.

The review is based on data gathered from 115 farms and other areas across Wales, Scotland and England, and determined that mammals account for between one-third and three-quarters of all songbirds lost to predation.

Farmer and vice-chairman of Songbird Survival, Robert Middleditch, said: ?Habitat is actually improving with new agri-environment schemes, along with increases in tree and hedge planting, but we must look at all the possible causes of decline, including predation. We have never subscribed to the popular view that predator and prey achieve a balance ? that is wishful thinking. Only genuine scientific evidence will persuade the Government to take steps to restore to its proper condition our biodiversity in general, and the population of our songbirds in particular.?