I was lucky enough to be invited out with the East Yorkshire bat group on their bat box check at Top Hill Low, which is a Yorkshire Water nature reserve. The promise was lots of Nathusius' pipistrelles, and it didn't disappoint with one in the first box we checked, though that one was a bit lively and made good its escape. The movement of very active bats from one box to the next made it difficult to tell just how many there were, as they are not ringed, but somewhere in the region of about seven seemed a decent guess. This has to make this reserve on of the UK hotspots for this species now.
We were joined by Tina Wiffen and others from the Northumberland Nathusius bat project, who we equally delighted with the chance to see and handle so many Nathusius pipistrelles.
I was especially interested in the wing fibre markings as this is supposed to be one way of separating these bats from the other UK pipistrelles, though for all the bats we saw, their size, robust appearance and hairy tail membranes made then pretty obvious.