Barn owls are back

Nesting boxes installed on the banks of rivers have halted the decline of barn owls in the UK.

In the late 1980s, numbers fell to an all-time low of fewer than 4,000 breeding pairs, a 70% drop in 50 years.

But the nesting chambers, situated on poles above the ground, have encouraged owls to return to breed near rivers such as the Eastern Rother, in south east England, and the River Humber in the north.

The owl population has now stabilised, said Colin Shawyer, director of the Hawk and Owl Trust based at the Zoological Society, London, speaking at the British Association's Festival of Science.

"About 75-80% of nesting boxes have barn owls breeding in them now," he said. "We need 6,000 pairs to make the UK population viable."

Breeding space

The idea for the nesting boxes came from plantations in Malaysia.

The boxes were introduced there to encourage owls back into the area to prey on rats and mice that feed on the fruit.

One thousand nesting boxes have now been put in place in England and Wales, on river banks being restored by the Environment Agency.

The nesting boxes, which look like dog kennels on poles, encourage the owls to breed.

About a metre long and half a metre wide, they have a pitched roof and an upper and lower chamber.

This gives the male and female owl separate living areas for when the female needs privacy for laying her eggs.

Natural habitat

Before the boxes were put in place, the river banks were allowed to return to their natural state, providing favourable habitats for small mammals like the field vole, which the owls hunt.

"Barn owls are a very good indicator of the health of the environment," said Dr Paul Raven of the Environment Agency.

Simple land management techniques, such as natural regeneration or removing culverts, are helping to restore the river as a living entity, he said.

The barn owl is one of several owls native to Britain. It is also known as the screech owl, because of its high-pitched scream.