Bats have been on earth about 50 million years. The only mammals (warm-blooded creatures) capable of sustained flight, bats are fascinating. They are part the web of life, playing a vital role keeping the earth and its inhabitants in balance. How? Bats help pollinate flowers and spread their seeds. Bats are the food of other creatures, such as hawks, falcons, owls and weasels. Some bats are indicator species which means changes to bat populations can highlight significant changes in wildlife.
They are also nature’s pest controllers. Bats eat insects – thousands every night. No British bat will ever bite or suck your blood. Bats in this country eat only insects including, ironically, the blood-sucking mosquito.
The bat’s insect-eating powers can reduce the need for pesticide sprays. However, although the bat is a friend to the farmer, modern farming is no friend to the bat. Most bats stick to the edges of hedges, streams and fields to roost (rest) and hunt. One of the reasons for the bat’s decline is the loss of woods and hedgerows. A gap in a hedge as little as ten metres wide can be enough to prevent a bat flying onwards.
Bats are also under threat from housing developments, airtight buildings, and motorways. It does not need to be this way. For instance, new buildings can be constructed with man-made roosts, farming can be designed to be more wildlife-friendly, and wildlife’s green corridors can be reconnected to join-up the wild places.
Fortunately, the breeding sites and resting places of bats are protected by law. McArthur’s Yard near the SS Great Britain on Bristol’s historic docks had been vacant for 20 years. The developers called in ecologists to assess the situation because there is a high chance the old buildings were housing bats.
Ecologists from Wild Service consultancy - a partnership between Avon and Gloucestershire Wildlife Trusts - conducted bat surveys at dusk and dawn. They discovered a small population of common pipistrelle bats roosting in the derelict warehouses. Pipistrelles are the most common group of bats, while the common pipistrelle bat the most often seen. These tiny bats weigh the equivalent of a 20p coin, and feed mostly on moths, midges and flies. A hungry pipistrelle - given enough wild places to forage - can eat 500 insects in an hour.
The lead ecologist got a special licence from the government’s nature adviser, Natural England, to permit work to legally continue, ensuring no bats at McArthur’s Yard were harmed during demolition. The bats were provided with bat boxes, and lighting on the site was designed so it would not disturb bat foraging routes at night.
Look for bats on the edges of fields or parks, just after sunset when the sky is still light. Check out the North Somerset Levels where bats are thriving. Thanks to insect-rich meadows and waterways, summer maternity roosts and winter hibernation sites, 15 – 20 per cent of the UK’s greater horseshoe bat live in the area.