The East Midlands is one of the best places to find bats.
According to the Forestry Commission, Nottinghamshire has some of the best habitats for bats.
Its rangers will be searching for the hairy armed bat in Elkesley Wood, near Retford, today. They are identify and sexing different breeds they find as part of continuing conservation efforts.
Last year they found 50 bats in just 18 boxes. 26 of these were found to be the very rare Leisler's bat.
The creature is second in size only to the UK's Noctule bat and has a wingspan of up to 33 centimetres.
– Adrienne Bennett, Forestry Commission Ecologist
"Bats have suffered big declines in the 20th century and are on the European Protected Species list together with otters and the dormouse. But Elkesley Wood is a hotspot and one of the best sites we have in the East Midlands."
Bats have struggled with the bad weather this year as they cannot hunt in heavy rain.
The Forestry Commission is working hard to maintain bat-friendly habitats in Nottinghamshire.