Alison Roberts reports on BATS: Wharfedale Naturalists final webinar of the autumn/winter season

DO you love them? Do you hate them? Are they the silent nymphs of a summer’s night as they fly across your garden or do they make you shudder? They often get a bad press so to set the record straight with a fascinating insight into the activities and behaviour of bats the Wharfedale Naturalists were delighted to welcome two bat devotees and serious scientists: Greg Slack, a consultant ecologist specialising in bats and Matt Whittle, consultant ecologist and Wharfedale Naturalists committee member. We all know that bats are the only flying mammals but did we know that the UK is home to 18 species of bats (Worldwide some 1,300 species) - 25% of UK mammal species, the tiny pipistrelle being the commonest. Weighing in at about 5 grams it can still consume up to 3,000 small insects in a night.

Among the very interesting things we learnt were the following:

There are more resident bats in the south of England than in Scotland as the south offers more suitable habit. They have a long life (41 years being the record) but a low reproductive rate. To conserve energy bats go into hibernation in winter when insects are in short supply and begin to emerge in early spring, feeding intensively to build up fat reserves against the following winter. Females begin to gather at “maternity roosts” whilst males roost on their own or in small groups. Females suckle their young for about six weeks after which the offspring are mature enough to catch insects and no longer require their mother’s milk. During their winter hibernation bats roost singly or in small groups in cool, quiet places with high humidity such as caves, old mines, fissures in rock faces, viaducts and even tower block thus sheltered from the weather and predators .

UK bats are insectivores, though worldwide different species eat a variety of other foods: nectar, fruit, even small fish, a few species even suck blood (hence some bad press). Different UK species use different insect catching strategies, echolocation being of utmost importance. Bats are not actually blind. They have small eyes with very sensitive vision but they augment this by emitting high frequency sounds which bounce back to their ears enabling them to detect objects in total darkness. The audience were treated to recordings of bat call frequencies and pitches of several bat species.

In Lower Wharfedale, the lowland water and woodland provide bat friendly habitat. In Upper Wharfedale Roosts are found within the protection of caves and mines. Sadly and for all the reasons that we are familiar with (loss of habitat due to intensive agriculture, herbicides, insecticides, loss of woodland etc) the bat population has declined dramatically over the last century.

All bat species are protected under the Wildlife and Countryside Act and protection extends to their roosts and associated habitat. This means that new building developments require a bat survey to assess whether bats or roosts are present and how they can be protected.

More information can be found through West Yorkshire Bat Group or The Bat Conservation Trust.