DEVASTATING flooding over the past year has had a disastrous effect on the region's recovering barn owl population.

Hawk and Owl Trust surveyors estimate that the breeding performance of the bird is the worst in 20 years following the wettest 12 months since records began in 1766.

Barn owls have increasingly nested in lowland river valleys over recent years, but the floods appear to have wiped out vast numbers of the voles, mice and shrew on which the birds prey.

The most recent research suggested there were only about 4,000 pairs left, but over recent years the population had started to recover, thanks in part to a scheme spearheaded by the Hawk and Owl Trust to erect nest boxes, including 200 along river valleys in North and East Yorkshire.

However, Trust workers checking boxes this year say many pairs did not lay eggs, and others produced young which died in the nest.

Colin Shawyer, trust director, said: "Taking the country as a whole, 2001 has been the worst year for barn owls since I began working with them in 1982. Everything points to a shortage of food.

"Detailed examination of over 600 nests sites revealed that small birds formed a large proportion of the prey, rather than the small mammals that normally dominate their diet.

"Birds are rarely taken except in extreme winters and even then only occasionally."

Mr Shawyer praised farmers and landowners who had supported the Trust's work and said: "The areas where the barn owl population has held up this year will be vital for recolonisation in the future.