Barn owls are facing a difficult time. Wet summers have upset their breeding patterns and suitable habitats are in decline. Rain in the middle of the year meant that males were starved of food and were unable to feed the female sitting on their eggs.

Females were then forced to leave the nests in search of food themselves, usually small mammals such as mice and voles, resulting in eggs being deserted.

The fashionable conversion of old barns has deprived the owl of its traditional habitat.

Fortunately, help is at hand on the Oxfordshire and Buckinghamshire boundary with a project involving the Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust and the inmates of Spring Hill open prison at Grendon Underwood, near Bicester.

Alarm at the decline of barn owls was raised about 2000 when Government environmental agencies realised something had to be done to halve the drop in numbers of these most beautiful of owls.

A barn owl project was set up along the county boundary and a small volunteer biodiversity team recruited. Dave Short is the volunteers’ team leader.

“Barn owls have declined because they have lost a lot of their natural habitats. Old barns on farms have been transformed into houses or offices.

“So this has meant there are fewer places for barn owls to live and breed,” said Dave.

In addition, some of the other habitats have gone too.

Modernisation of many homes has led to wooden eaves being replaced by plastic, and out in the countryside, tidy-minded landowners have been chopping down old hollow trees, which traditionally made an ideal location for a nest.

One answer was to put up wooden nesting boxes at suitable sites.

The teams actually found willing help in the inmates of the open prison who made the boxes in their workshops as a contribution to the local community.

“However, while the prisoners do not charge us for their manpower we do accept donations from farmers or landowners to help pay for the cost of obtaining wood,” said Dave.

Initially, 25 boxes were installed and by last year there were 164 in various locations.

“We have had a lot of co-operation from BBOWT and have been able to put up boxes on the edges of woodlands on their reserves,” said Dave.

Among the locations where boxes have gone up or are planned are at Calvert lake, between Bicester and Winslow, at Rushbeds reserve, near Brill, woods at Finmere, near Bicester, and the Waddesdon Manor estate.

After boxes have been up for a while the volunteers check whether they have been occupied and if owlets have been reared.

Last year was one of the best so far for results. Out of the 150 boxes installed, 22 were occupied, while about half were visited by owls scouting for potential sites.

More volunteers would mean a larger number of boxes could be monitored.

Records on barn owls and their owlets are passed on to the British Trust for Ornithology as volunteers ring the owlets they find in the boxes.

In addition to providing the boxes the teams and volunteers give advice to farmers and landowners on management.

Dave said: “We encourage landowners to allow hedges next to roads to grow up to a height of about 3m (10ft).

“This means that owls, when flying over a hedge will achieve a sufficient height to cross a road.

“Otherwise, with lower hedges, owls tend to swoop downwards in the search for prey, and become low enough to strike or be struck by vehicles.

It is estimated that about 50 per cent of barn owl deaths are due to road kill.”

There is also some growing concern at the trend to have fewer areas set aside at the edges of fields leading to a decline in the food supply of mice, voles and rats for owls to hunt.

Set aside was a scheme promoted by the European Union years ago to help reduce grain mountains.

But now more set aside land on the margins of fields is being ploughed up for food production.

In 2007, the biodiversity team produced an action plan.

Key factors were: promoting barn owl conservation; safeguarding habitats; putting up boxes; encouraging recording and monitoring; research into barn owl ecology; and activities to raise awareness.

As well as their interest in barn owls, the volunteers have begun to watch the reduction in the populations of tree and house sparrows and kestrels.

These will doubtless offer scope for future research.