Bat roosts in trees
The vast majority of our work focuses in bats roosting in buildings, but all Scottish bat species use trees to roost. Identifying tree roosts can be challenging, especially in summer when leaves can make for tricky viewing. Fortunately, there are some features and signs we can use to identify roosts (and roost potential) when conducting tree surveys.
Bat Signs in Trees
The signs of a roost in a tree are the same as in buildings. If we spot droppings around a roost entrance, smear marks (from the oils in bats’ hair), or hear ‘chittering’ sounds on a warm day, then we have a bat roost. When bats are roosting further up, this can be particularly challenging. That’s why we regularly work with tree climbers who go up into the tree to complete a close-quarters visual inspection.
We are likely to combine working with a tree climber with endoscoping tree holes looking for bats roosting, or performing a bat activity (or presence/absence) survey to see bats entering and exiting the roost.
What Do Bats Look For?
Just as in buildings, there are a few features bats look for when choosing a tree roost. These features create crevices or voids that the bats can use to roost during the day. Rotted-out holes, cracked or split branches, or areas of loose bark can all provide enough space for a bat (or colony of bats) to rest safely.
Large deciduous trees with ‘rougher’ exteriors create more opportunities for roosting than smoother, smaller, or evergreen trees. Old oak and ash are frequent favourites due to their longevity, size, and tendency to have cracks and crevices form.
Bats do not create their roosts, but instead use existing features made naturally or by other animals.
Bat Roosts in Trees are Protected
All bats and bat roosts are protected in the UK - including bat roosts in trees. All roosts retain their protection when bats are not present, and disturbing or destroying a roost without a derogation license is a criminal offence. ‘Not knowing’ about a bat roost is not a valid defence if you begin works and discover a roost is present.
If you're considering tree felling or surgery work, it's always best to seek professional advice. Our bat specialist ecologists are here to help with any queries you may have about bats in trees.
If you need a bat survey (or think you might) get in touch with our team of specialist ecologists!
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