The barn owl population has declined 70% in the last century

Once a common native bird, the species has seen a decline in its population over the last century of 70%.

Now research being carried out at the University of York will look into the owls' habitat and eating habits.

The data, which is being collected in the Derwent Valley in North Yorkshire, will be used to aid national conservation plans for the bird.

Intensive farming

Nick Askew, of the university's department of biology, said: "I have found that the area could hold one of the densest populations of barn owls in Britain today."

The decline of the barn owl has been blamed on intensive farming, resulting in the loss of habitat and nest sites.

Barn owls require areas of rough grassland habitat where they hunt their preferred prey - the field vole.

The university hopes its research will be taken up by farmers, who can use government cash to create suitable habitats for wildlife.

Mr Askew said: "In Britain today there are thought to be more barn owls in captivity than in the wild."