Alarm calls over plummeting population of the nut-smashing recluse

The hawfinch, with its habit of lurking in deep foliage while using its powerful jaws to crack open seeds impregnable to other species, has long been considered the recluse of the British bird world.

The hawfinch, with its habit of lurking in deep foliage while using its powerful jaws to crack open seeds impregnable to other species, has long been considered the recluse of the British bird world.

Butthere is now a more worrying reason for the difficulty in spotting the species – its population has more than halved in the past 10 years. A study by the Royal Society for the Protection of Birds published yesterday has found that the population of hawfinches has plummeted from about 6,500 pairs in 1990 to as few as 3,000.

Ornithologists are uncertain of the reasons for the drastic decline in the stocky pink-coloured finch, which can exert a force of 110lb per square inch between its bill to allow it to feed on nuts and seeds.

Experts are asking birdwatchers to redouble their efforts to spot hawfinches, which are made difficult to see by their liking of dense tree foliage and lack of conspicuous song. Bird spotters are often only alerted to its presence by the sound of groups of hawfinches cracking their favourite food, which includes the pits of damson, hornbeam, sloe and cherry. Its scientific name, Cocco-thraustes coccothraustes, means "one who can break open kernels".

The study, based on bird-watching records between 1975 and 1999, showed that although the finch has been declining throughout that period, the drop has accelerated sharply since 1985. Dr Richard Gregory, head of monitoring for the RSPB, who co-wrote the study, said: "It is clear from the records that its population is declining and that has accelerated over more recent years. We need to know more about the hawfinches out there to explain why. It is possible that tree loss from the great storms is a major factor. Mature trees provide the fruit and cover that provides their habitat. The loss of so many trees might have affected that adversely."

Another factorcould be the loss of the traditional British orchard, an important food source, which has declined by between 50 per cent and 65 per cent since the Seventies. The growth of competing species such as the grey squirrel may also be forcing out hawfinches.

The RSPB study, published in the journal British Birds, also found that the hawfinch remained abundant throughout continental Europe.

Birdwatchers are being asked to report sightings of the hawfinch to their local county bird recorder.