A centrally heated box is to be used to lure a rare species of bat to a Northumberland forest.
Forest chiefs want to encourage 50 pipistrelle bats to breed
The Forestry Commission hopes the "des res" will tempt about 50 female pipistrelle bats to move in and breed.
Roosting bats need warmth and often live near chimney stacks. Their new home in Kielder Forest, near Bellingham will be kept at 27C.
The move comes after the demolition of an unsafe building on the site where the bats used to lived.
Forester Vicky Pearson said: "There's been a little bit of research in Scotland on using heated bat boxes, but it's really cutting edge stuff so we're not sure how the bats will react.
"There are no off-the-shelf designs, so we have had to manufacture the box in-house.
"To gauge its success, we've put up two more conventional bat boxes nearby. It's finger's crossed they take-up our invitation."
The heating will not be on all year round - it will only be on in the spring when bats start to look for roosts before giving birth in June and July.
Ruth Hadden, an ecology consultant, who advised forest chiefs on the project, said: "The box has divisions inside to resemble crevices. It's quite small because the bats like to pack closely together to keep each other warm."