THE Forestry Commission is calling on nature-lovers to go batty this coming weekend.

For the first time they have asked the public to join their annual bat-box survey in Dalby Forest, near Pickering.

Every summer, wildlife ranger Charles Critchley and his team check the 350 roosting boxes in the forest.

The woodlands have become an important stronghold for seven or eight species of the threatened mammal - whose numbers nationally have declined by as much as 90 per cent during the past 100 years.

The bat boxes are a key part of the long-term conservation effort. Bats are very choosy about where they roost, and boxes have been installed in different locations to offer species like pipistrelle and noctule bats a good selection.

By checking the boxes each year, rangers are discovering more about the health and diversity of the local population and how bats use the forest.

"It's the first time we have invited the public to join the survey and it will be a fantastic opportunity to find our more about bats and their habitat," said recreation ranger Brian Walker.

"Bats are social animals so we usually put three boxes on a single tree - it's a bit like having a woodland tower block. Then they can move around depending on factors such as the weather conditions."

The bat walk will be led by Charles Critchley and sets out from Dalby Forest Visitor Centre at 2pm on Sunday. The cost is £3 for adults and £2 concessions. For details, contact (01751) 460378