Halloween: Woodchester wildlife that goes bump in the night

The rafters of Woodchester mansion are home to a colony of greater horseshoe bats. The big, open space in the abandoned mansion is a perfect hideaway for these bats: cool, quiet and out of the way.

During the night, these nocturnal mammals are out in the surrounding woodland, voraciously feeding up on beetles, moths and flies in preparation for their forthcoming hibernation. The greater horseshoe is categorised as rare by Natural England, and the Autumnwatch team had to apply for a licence to approach and film the roost.

October is the month which sees greater horseshoes mating. Following insemination, a vaginal plug forms inside the female storing the sperm until fertilisation occurs in the spring. In a matter of weeks, the whole colony will leave the mansion for their winter roosts, where they'll hibernate through the cold months.

Unlike the fluctuating conditions inside Woodchester mansion, the location the greater horseshoes select for the winter (tree hollows or caves) will be regular in temperature and humidity, allowing these small mammals to hibernate undisturbed. The bats are loyal to their roosts and will return to the same location year after year.

Woodchester is also home to the greater horseshoe's cousin, the lesser horseshoe. As the name suggests, the main difference between the two species is their size. Greater horseshoe bats are the size of a pear, whereas the lesser horseshoes are more like the size of a plum.

These are Britain's only bats to have a horseshoe-shaped fleshy structure called a nose-leaf surrounding the nose, which amplifies the ultrasonic calls that the bat emits when searching for food. The horseshoe bats are unique in that all of Britain's other bats echolocate using their mouths alone.

If you would like to know more about the species of bats in your area and would like to get involved in their conservation then contact the Bat Conservation Trust who will be able to put you in touch with your local bat group. There are over one hundred throughout the UK. Martin has blogged about getting more involved with bats.

The Autumnwatch team also struck upon a row of badger latrines in the fields surrounding the mansion. The badgers use their faeces to mark their territorial boundaries, giving notice of occupation to other potential badger intruders. Researchers at Woodchester bait badger food with harmless, coloured plastic discs and record where they are distributed to in an attempt to determine the different badger clan territories around the park.

(BBC Gloucestershire have made a photo slidehow of the Autumnwatch team's visit to Woodchester. The visit even made BBC Points West.)

So armed with all this infomation about wildlife that goes bump in the night, get into the Halloween mood by taking a night time woodland walk. Listen out for the sounds of surrounding wildlife: the eerie hooting of tawny owls from the tree tops, female foxes screaming in the distance, deer rustling close by in the undergrowth and, of course, the unmistakeable whoosh of bats as they fly past your ear...

(Chris Packham has created a downloadable guide to sounds of the night for BBC Breathing Places.)