Blog | The Importance of Bats in Our Towns and Cities
To describe bats as “urban” might, to some people, suggest that they are in some way invading our human space. The truth, however, is that humankind has spread into and redefined the spaces that were the bats’ habitats long before we were around.
There is fossil evidence that points to the fact that there were bats flying around over 55 million years ago, long before humans were around. Yet it is recent human activity, such as urbanisation, the removal of hedgerows and the use of chemical sprays on crops that are endangering their survival.
• There are around 1,300 known species of bat across the world, and more are being discovered every year. In Britain, there are eighteen species, of which eight have been recorded in urban environments.
• They account for almost a third of the mammal species in the UK although they only account for 1% of the UK mammal population, numbering around 2.5 million bats. There are two main species of the Pipistrelle bat, the most common UK bat, which accounts for two million bats, meaning that the other sixteen species are relatively rare.
• They occupy a wide range of habitats, including wetlands, woodlands, farmland, as well as urban areas.
• They are most commonly seen at either at dusk or during the night in spring and summer when they are flying in search of insects. All the UK species of bat feed exclusively on insects, especially moths, mosquitoes and other flies. The most common urban bat, the common Pipistrelle, which is also the smallest UK species, eats up to three thousand insects in one night!
• They are the only mammals that can truly fly rather than simply glide between trees. Bats have fingers that are adapted to support wings of leathery skin.
• Contrary to the saying “as blind as a bat”, bats are not at all blind. In fact, they have small eyes that can see quite well in the half-light.
• The popular understanding that bats sleep upside down is true, however, they also rest, mate and give birth upside down too.
• Like humans, bats generally give birth to one baby at a time and these babies are called pups. Bats live surprisingly long lives for small mammals with a life span of five or six years common for a Pipistrelle, although some species can live for over thirty years.
• They use echolocation to navigate and locate their food. They achieve this as they fly along by making high-pitched sounds that bounce off obstacles producing an echo.
• They are clean, gentle and intelligent, and since they are top predators of common nocturnal insects, they are sensitive to changes in land-use practices.
• They roost in a variety of buildings but prefer clean, draught-free buildings, disliking dust and cobwebs, dispelling another myth. Away from the urban jungle, bats roost in caves, hollow trees and behind tree bark where it has started to peel away. Bats may also roost in bat boxes.
• They hibernate during the winter months, although they might occasionally leave their roost to hunt for food during this time.
Problems Facing the Urban Bat
As human development has progressively encroached onto woodland and other wild spaces, bats have had to adapt their behaviour to roost in buildings and can be found in a variety of structures including houses, bridges, barns, and churches. One of the biggest threats the urban bat faces is a loss of these roost sites as houses and industrial sites are modernised.
One of the reasons the urban environment is generally less attractive to bats is because of the lack of vegetation which means there is a consequential shortage of insects to feed on. In the drier parts of the world, urban areas generally have artificial ponds and other water sources that can help local bats by attracting insects.
Several species of bat roost in trees, and, despite the presence of parks and green spaces, the number of trees in town and city centres across the UK has been declining over the years.
Other problems facing the urban bat are getting trapped in buildings, hit by vehicles, or having their roosts deliberately disrupted by people who don’t want bats in their attic. Bats are also potential prey for the domestic cat.
As nocturnal mammals, one of the biggest issues facing them is the constant night-time glow that modern cities emit from windows and streetlamps.
Light pollution may result in bats being compelled to abandon their roost, which can have a significant effect on the prospects for the future of the colony.
Artificial lighting can also affect the bats’ use of commuting routes with excessive light having been found to act as a barrier, leading to bats detouring to their feeding locations with a consequential addition to their energy requirements.
Creating a Bat Friendly Urban Environment
There are a number of ways that towns and cities can create a more bat-friendly environment. A planner, for instance, can acknowledge that bats use linear features such as tree lines for commuting and should create a wildlife corridor for bats from their roost that leads them to a natural area. This would help bats avoid main roads, create feeding opportunities for them and design around bats’ natural inclination to follow linear features. If there are no trees, bats are likely to follow alternative and potentially more dangerous lines such as main roads where there is the risk of being killed by cars.
Research has revealed that tree roosts in urban areas are almost exclusively conﬁned to larger trees. However, it is these larger trees that are habitually removed from avenues and parks because they are considered a threat to public safety. Reducing the number of such large trees could lead to a decline in the population of tree-dwelling species of bat and therefore administrators should try to preserve as many of these trees as possible.
Furthermore, large branches can be supported by ground anchoring and people can be prevented from entering danger zones around weaker trees by the planting of thorny bushes within these areas to deter pedestrians.
Where the preservation of trees isn’t possible, providing artiﬁcial roosts in the form of bat boxes can help to provide new roosting opportunities for some species of bat.
Creating bat-friendly gardens with plants that attract insects that bats feed on, helps to keep the numbers of undesirable insects down, particularly in the summer, and is another way to help the urban bat.
The problem of the damaging effects of light pollution on bats has been taken very seriously with a number of different experiments in street lighting having been carried out in various parts of the world. The Solareye80’s in-ground solar light which is designed to provide 360-degree visibility at night now comes with a “Bat Hat”, the standard product having been re-engineered by adding a little hat that reduces the upwards light spillage by around 98%. This design feature makes this light the perfect choice for areas in which it is important to reduce the impact of artificial lighting on bat colonies. We work in conjunction with Ecologists and have consulted the Bat Conservation Trust to ensure that we play our part in helping the bat population of the UK thrive.
Simply get in touch with us to learn more about the Bat Hat and how it can be used for your project.