Animal homes | Bat boxes

Did you know that the populations of most of our bats has halved in the last 50 years?

However, eleven of Britain's fourteen resident bat species have been found to roost in bat boxes, and six species have used them for breeding. So a difference can made just by following the simple method below.

Why the decrease in bat numbers? Loss of hedgerows, old mature trees for roosting and hibernation, building renovations and human disturbance have all played a part for the decrease. The use of chemicals in agriculture and domestically have had a direct effect on bats. Britain's most widespread and common species is the tiny pipistrelle. It is a bat that which is often associated with modern buildings and can often be seen dashing and darting in a zigzag fashion.

Bat boxes are a great way of encouraging bats into your area. It has been known for bats to roost in boxes, as many as 60! However if you have some old trees which you can manage sensitively these would be ideal especially if there are cracks and holes in the trunk (a habitat also perfect for owls and other birds).

All British bats feed on insects; they need continuous supply of food during the summer. Leave dead wood in habitat piles to encourage invertebrates, vital food for bats and small mammals. Bat boxes are more valuable at sites where there is an ample food supply of insects, perhaps near a pond or waterlogged ground.

Method

  1. The box should be large enough to allow maternity colony to cluster together to keep the babies warm. The box maybe used throughout the year, except in very cold weather (below -4'C).
  2. Use untreated rough sawn timber, this allows bats to cling and crawl into the box. The timber should be at least 25mm thick, and the box should be constructed to be rainproof and draught-free.
  3. Site the boxes as high as possible in sheltered areas, where they are exposed to the sun for part of the day. There should be a clear flight to the box entrance. A large tree can hold up to three boxes. Boxes should not be disturbed, so check for occupancy by watching at dusk for bats to emerge.

Bat box dimensions

Batbox dimensions

Aerial view of bat boxes, with orientation

Aerial View of batboxes, with orientation

related links

English Nature Tel 01635 268881 If you think a bat roost is under threat or disturbance - it is illegal to kill, harm or injure bats under the Wildlife & Countryside act 1981.
Bat conservation trust Tel 0171 6272629 For more facts on bats, do surveys and go bat detecting!