Bats begin to hibernate as night-time temperatures fall, but they can still be seen on warmer nights. Some are still turning up at swarming sites – the bat equivalent of a late night party – where males appear to be showing off to each other and females seem to be looking for potential mates. At Box Mines, which has been monitored by Wiltshire Bat Group for many years, some animals have been found to travel more than 20 miles to reach the site. On a given night, the site can have literally hundreds of bats, yet be almost deserted on another night. How the bats co-ordinate this activity – presumably without the advantage of social media – is a mystery.
As the nights get colder, and certainly by early November, most animals will be hunkering down for the winter. They will be using hibernation sites and be dipping in and out of torpor, and coming out to feed only occasionally. Foraging trips are short, and so it is vital that they have plentiful food supplies within easy reach of the roost.
Sympathetic agricultural management is very important, but we can all also do our bit to help. Garden ponds provide an excellent source of insects (and bats also like to drink when they wake from hibernation). And by switching off our outside lights at night and pulling the curtains, we can make sure that bats are not forced to make lengthy detours to avoid light pollution.
For the latest information on bats and their conservation status take a look at our Review of the Population and Conservation Status of British Mammals: Technical Summary or visit the Natural England Access to Evidence bat webpages here.