Barn owls

First issue May 1997

For a printable (PDF) version click here

See also: wild birds and the law

Barn Owls are special birds, known by most people and with much associated folklore and legend. However they can be very hard to find in the wild now. Numbers have dropped dramatically by 60% or more since 1932, so that now there are only about 5,000 pairs in Great Britain. In Essex there may be no more than 30 pairs still breeding, mainly in the coastal strip and especially Dengie and Foulness, as well as on grazing marshes such as our Tollesbury Wick nature reserve. In 1932 there were an estimated 500 pairs in the county which means that 94% have been lost!

Why are they declining?

The reasons for their decline are many and can be summarised as development and progress. One of the two major causes is the loss of nest sites. Contrary to popular belief, in this part of the country as many Barn Owls nest in holes in trees as in barns and other buildings, although in the south-west where it is wetter 95% of nests are in buildings. Unfortunately both these types of site have declined in Essex: barns because of conversion to domestic use, and trees due to Dutch Elm Disease, the big storms of recent years, the destruction of hedgerows with mature trees and loss of woodlands.

The other main cause is the loss of feeding habitat. Barn Owls need areas of rough grassland especially along hedgerows and stream valleys. These areas have vanished because of the more intensive agricultural systems practised in modern times, especially in this part of the country. Other factors include roads and traffic, as Barn Owls often hunt along road verges where there is still some grassland. Being fairly slow flyers they can't avoid even slow-moving cars and it is estimated that there are 5000 casualties a year nationally.

The climate has also been unfavourable in recent years with wetter and windier conditions becoming more frequent. Barn Owls become waterlogged very easily and this prevents them from hunting efficiently as do high winds.

Confusing the issue is the situation with captive Barn Owls which outnumber wild ones in Britain. These are often released by well-meaning people into areas that are unsuitable. Lacking experience of the wild many of them die of starvation. It is now illegal to release them into the wild without a licence from the Department of the Environment.

Signs of Barn Owls

Pellets are formed from the indigestible remains of the prey items eaten by owls (and are also produced by diurnal birds of prey and many other types of bird). They are coughed up regularly around the roost before the bird goes off to hunt and so are an excellent sign of owl activity in an area. In Barn Owls they mainly consist of fur and bones of small mammals, but sometimes they can include, for example, feathers and beetle wing cases. The pellets are distinctive in that they are shiny, black, sausage-shaped and about the size of a man's thumb but care is needed because after a few days they lose their shine and the size can vary, especially if food is short. Other owls' pellets are generally bigger, not shiny, and usually grey.

Other signs of Barn Owl presence are chalky white droppings streaking the building or tree around the nest and the noise of the chicks which is a bit like loud snoring.

What can be done?

Farmers are the people who can do most to benefit Barn Owls and many farmers are justifiably proud to have them on their land. They can be a positive benefit to farmers, feeding as they do on the small rodents which can be pests. In the past they were welcomed into barns exactly because of this.

Boxes in outbuildings and trees will encourage Barn Owls into the area but only if there is suitable feeding habitat in the vicinity. This can be provided by leaving areas of rough grassland or unmanaged field margins, along with well maintained and structured hedgerows. These provide good habitat for the rodent species that the owls prey on. These measures will of course benefit other wildlife as well.

Another way of helping is to take extra care when using poisons. The new powerful rodenticides introduced to cope with rats which are resistant to Warfarin should be avoided. Something else which can be easily done is to cover water troughs and tanks which can often lead to drowning, the most common recorded cause of death in Barn Owls. Tanks can be covered with chicken wire while a thick plastic mesh , such as the bottoms of bread trays, will save Barn Owls while still allowing livestock to push it down to drink.

When working in barns where Barn Owls nest extra care should be taken - it is illegal to disturb them under Schedule 1 of the Wildlife and Countryside Act (1981). If the work is absolutely necessary then an alternative site should be provided by placing a nest-box in a nearby tree or building. If you are involved with converting a barn make allowances for owls in the plans by setting aside a section of the roof space for a nest site, with a window for access.

Nest Sites for Barn Owls

Barn owls will only use a nest box if the land around is suitable hunting territory. Where this is the case, a nest box may make all the difference. The design below is for a box to be placed high up inside an open building like a barn. Scatter some wood shavings inside and clean it out every couple of years.

You can convert an existing closed building by cutting an 'owl window' about 1 metre down from the gable end and placing the nest box on a platform at least 1 metre square inside the loft. Close the platform off at the back, but include a hatch so you can get in to clean it out occasionally. More details from the Hawk and Owl Trust (address below).

More information

For more information contact the Essex Wildlife Trust or:

Hawk and Owl Trust,
c/o Zoological Society of London,
Regent's Park,
London NW1 4RY

who can provide more information about habitat creation and nest sites.