You’d imagine that on a relatively small island group like the UK we’d have a pretty good grasp of our mammal fauna, but you’d be surprised by just how much we don’t know. Bats are the classic example and now is the time to start keeping your eyes peeled.
18 species, nearly 25%, of our mammals are bats and 17 of those are resident, yet as recently as 2010 Alcathoe Bat was added to the list of residents, and it was only in 1997 that Nathusius’ Pipistrelle was confirmed as being more than just a migrant. Our knowledge of bat distribution and abundance is continually expanding and more recently there has been more emphasis placed on the significance of bat migration. Like so many Palearctic birds, some northern bats head south during the winter, and some will undoubtedly pass through the UK. The most likely migrant is Nathusius’ Pipistrelle, but Noctule may also make longer movements, and a number of vagrants bats have turned up such as Part-coloured Bat & Kuhl’s Pipistrelle.
Richard Moores has been gathering data on bat migration in the UK and if you have any sightings of bats at coastal migration points he’d be very keen to hear from you (firstname.lastname@example.org).