Some of the rarest bats in Britain have made Newark Park their home. At least eight different species have been spotted, including Daubentons, Long Eared, Natterers and Lesser and Greater Horseshoes.
They emerge at dusk to hunt insects. Their favourite are the dung beetles that feed on the cowpats left by the grazing cattle in the parkland.
The bats use the lines of trees in the woods to find their way around the estate. They act like mini bat motorways. On a warm summer's evening you can see them flying looking for their next tasty meal.
It's hard to identify the different bats - they're small and fly very quickly. We use specialist bat detectors that pick up on the sounds they make to help us find out which type they are.
The echolocation calls of the Natterer's bat are very quiet. On a bat detector their calls are heard as irregular, rapid clicks. Some people say that they sound like cellophane being crumpled.
In contrast, the calls from the Daubenton bats sound like a machine-gun series of regular clicks that last for between five and ten seconds.