The Relationship Between Bats and Trees
Trees are fundamental to bats’ survival in the UK, serving as a primary habitat and an essential food source.
In this article, we discuss the intricate relationship between bats and trees and the different roles trees play in supporting bat populations.
By understanding bats’ specific needs, we can take measures to protect both trees and the bats that rely on them.
We also cover bat protection law and the legislation related to performing tree surgery on trees with “bat potential”.
Why Do Bats Need Trees?
Bats rely on trees in many ways, but most importantly, for shelter, food and navigation. We’ll discuss these in further detail below.
Daytime Roosting
Roosts provide bats with a safe, sheltered place to rest during the day. As crevice dwellers, barbastelle and pipistrelle bats squeeze into tiny gaps within trees, like cracks, splits, or behind loose bark. Other species prefer more room, opting for woodpecker holes or rot cavities as their daytime hideaways. These varied roosting habits showcase bats’ adaptability to different tree features.
Summer Roosting
In the summer, breeding females require warmer conditions to raise their young, so they often choose shallow tree cavities or areas beneath loose bark that offer higher temperatures. However, bats may shift to damper rot holes during hot spells to avoid dehydration.
Hibernation Roosting
Bats require a secure, damp roost with a consistent temperature for winter hibernation. A hollow tree trunk can offer ideal conditions for numerous bats to hibernate and await warmer weather safely.
Temporary Refuge
Bats use trees as safe spaces to consume their prey while foraging or to seek shelter in bad weather.
Food
All UK bats exclusively eat insects. Trees attract a diverse variety of insects, which bats capture using two methods: ‘hawking’, where they snatch insects mid-flight, and ‘gleaning’, where they forage insects from surfaces like spiders from webs.
Navigation
Bats employ echolocation features to navigate. Large trees and hedgerow tree lines serve as landmarks along regular commuting routes that bats use to travel between their roosting sites and feeding areas.
Threats to Bats and Their Habitats
Despite bats’ strong relationship with trees, several threats jeopardise these natural habitats. Tree removal or heavy pruning due to development, agriculture, or safety concerns can lead to significant habitat loss for bats. Trees may also be lost due to natural processes like weather damage or disease, further threatening the availability of suitable roosts. Bats are particularly sensitive to habitat disturbance. Not only does tree removal or heavy pruning directly impact bat populations, but indirect effects from development, such as increased lighting, noise, and human activity, can disrupt their natural behaviours.
Trees, Bats and the Law
In the UK, the Wildlife and Countryside Act 1981 and the Conservation of Habitats & Species Regulations 2017 protect all bats and their roosting sites. This legal protection makes damaging or destroying a bat roost illegal, even if bats aren’t present.
Since bats and their roosts are protected by law, tree surveys are crucial in ensuring compliance with these laws. Before any tree work begins, a qualified arborist must assess the potential impact on bats.
Trees with features that bats could use for roosting should be identified and categorised based on their “bat potential”. If a tree has high bat potential, an ecologist may need to conduct a survey and, if necessary, apply for a European Protected Species (EPS) license to allow any work to proceed legally.
If you’re uncertain about working on trees with “bat potential” while in compliance with the law, contact North London Tree Surgeons today.
We have experienced arborists who can advise you on the best way to proceed with your project in a bat-sensitive manner.
Furthermore, we’ve built great relationships with some exceptional ecologists who we can call upon for more detailed ecological surveys.
Bat Conservation
By preserving trees and considering bats in tree management practices, we can all safeguard the future of these remarkable creatures.
For more information regarding bat conservation, visit the Bat Conservation Trust website.
They have also created this helpful poster in in collaboration with Mammal Next Door.
Tree Preferences Of Different Bats
Not all bat species have the same preferences for trees. Different species prefer different features depending on the tree’s type, location, and season.
Pipistrelle Bats (Common, Nathusius, Soprano)
These small bats are primarily crevice dwellers, often roosting behind loose bark or in small splits and rot holes in trees. While they are known for roosting in buildings, they also adapt well to tree roosts. Pipistrelles are widespread across rural and urban areas and forage in diverse environments, including gardens, parks, and forests.
Barbastelle
This species prefers roosting behind loose bark or in tree splits, often in ancient deciduous woodlands with a dense understorey. They are fast, agile flyers and specialist foragers, adept at hunting in varied habitats.
Natterer’s Bat
A crevice-dwelling species, Natterer’s bats roost in both deciduous and coniferous woodlands. They are often found in broad-leaved forests, hedgerows, and tree lines near agricultural land. This adaptability makes them one of the more versatile tree-roosting species.
Brown Long-eared Bat
This species roosts in both buildings and trees. When roosting in trees, they may be found closer to the ground, in more cluttered environments with dense surrounding vegetation. Brown long-eared bats prefer deciduous woodlands for foraging, using their slow, fluttery flight to glean insects from leaves and bark.
Noctule
As the UK’s largest-sized bat, Noctule bats predominantly roost in trees throughout the year, favouring rot holes and woodpecker cavities. Both males and females use these roosts, and males often defend them during mating season to attract females. Noctules are known for their long-distance foraging, sometimes travelling up to 10 km from their roosts to hunt insects while in flight.
Bechstein’s Bat
Most frequently found roosting in old woodpecker holes, Bechstein’s bats have a strong preference for oak and ash trees. These bats thrive in wet woodlands with dense vegetation and small streams, which provide ample opportunities for both roosting and foraging.
For bat friendly tree surgery performed by an experienced arborist or tree surgeon North London Tree Surgeons are ready to help.
Bats And Trees FAQs
Do bats nest in trees in the UK?
Most bats in the UK roost in trees. Approximately 75% of British bat species roost in trees, while others prefer human-made structures due to limited suitable tree habitats.
Why do bats hang from trees?
Bats hang from trees to sleep and avoid predators. Their leg muscles have evolved to hang upside down, so this is their most relaxed position.
How are trees important to bats?
Bats use trees as roosting sites throughout the year. Trees serve as breeding roosts in summer, mating roosts in autumn, hibernation roosts in winter and temporary roosts throughout the year.
Can you cut down a tree that bats live in?
No, cutting down a tree that bats live in is illegal. It is an offence to kill or cause significant disturbance to these protected species deliberately or to destroy or damage a breeding site or resting place used by them.
