Swarming bats.

A return to site for a dawn survey to find out if the bats are returning to roosts in the building being surveyed sounds great until the alarm goes off at 03.50. It is even harder to drag yourself out of bed if you only got back from an evening bat survey at 22.30.

One of the wonderful sights of dawn surveys is of groups of bats ‘swarming’ around before they enter their roost. This morning was slightly different. From 04.30 there were a few Common Pipistrelle bats flying past the building, continuing to feed, and a few Natterer’s bats feeding around a two storey entrance to an open section of the barn. From 04.52 the Natterer’s bats increased in number until there were seven ‘swarming’ around the entrance to the barn at one point. The bats circled around the entrance to the barn before flying inside and then flying around inside the building. This included flying around in the roof space and flying into the open first floor storage areas.

The bats continued to fly in and out of the barn until around 05.30. Standing in the entrance to the barn I had counted 26 bats entering but only 22 leaving. There are other entrances to the barn so they may have exited elsewhere or it may be that some remained, roosting in the cavities in brickwork and splits in the beams that can be found throughout the building.

I’ll have to return to site with the night shoot video recorder for another dawn survey to film the ‘swarming’ and try and take some of the Trainee Volunteer Bat workers along to practice with their bat detectors and to see ‘swarming’ bats.