Wildlife and bats: why your tree surgeon might stop work

Because the law gives bats, their roosts and active birds' nests protection that overrides the job. Every UK bat species is a European protected species, and it is an offence to damage or destroy a place a bat uses for breeding or resting, whether or not a bat is there at the time. A tree surgeon who sees the signs of a roost partway through a job is expected to stop work in that part of the tree, and either change the method so no offence is committed or get a licence from Natural England before going on. The same applies to an active bird's nest. It is frustrating, and it is not the contractor being awkward.

This guide is general information, not legal advice.

What the law actually says about bats

Two pieces of legislation apply. Bats are listed under the Wildlife and Countryside Act 1981, and as European protected species they are covered by the Conservation of Habitats and Species Regulations 2017. Between them, it is an offence to:

• deliberately capture, injure or kill a bat
• deliberately disturb bats in a way likely to impair their ability to survive, breed, rear young or hibernate, or to affect the local distribution or abundance of the species
• damage or destroy a breeding site or resting place
• intentionally or recklessly disturb a bat while it is occupying a structure or place it uses for shelter, or obstruct access to it

The third of those is the one that catches tree work. The wording in regulation 43 is different from the others: the capture, killing and disturbance offences require the act to be deliberate, but damaging or destroying a breeding site or resting place carries no such qualifier. In practice a roost can be damaged unlawfully by someone who did not intend it and did not know it was there, which is why contractors are careful and why "I had no idea" is a weak position. Penalties on conviction can run to six months' imprisonment and an unlimited fine.

A roost is protected whether or not bats are in it. Bats return to the same features year after year, and a tree can hold a maternity roost in summer, a hibernation site in winter and a night roost in between.

The signs a tree surgeon looks for

A check from the ground, and again from the climb, is normal practice. The features that suggest a tree may hold bats are:

• woodpecker holes, knot holes and old rot holes
• splits, cracks and shear planes in limbs, especially vertical ones
• lifted or loose bark with a cavity behind it
• hollow limbs and trunks, and the openings into them
• dark staining or polished, smooth wood around a hole, worn by fur
• droppings below an entrance, which look like mouse droppings but crumble to a glitter of insect fragments
• flies around a hole, or a faint ammonia smell
• dense ivy on a mature trunk, which is a roost feature in its own right

None of these proves bats are present. They mean the tree has potential, and the next step is an assessment rather than a chainsaw. Mature ash, oak, beech, willow and old ivy-clad trees near water or woodland are the usual candidates. The Arboricultural Association and the Bat Conservation Trust both publish guidance for arborists on assessing bat habitat before work.

What happens if bats are found

1. Work stops in that part of the tree. Not necessarily the whole job, and a crew can often carry on elsewhere.
2. Nothing is blocked, moved or cut around the feature. Obstructing access to a roost is itself an offence.
3. Advice is taken. The National Bat Helpline, run by the Bat Conservation Trust, is on 0345 1300 228 and gives free advice, including arranging for someone to look at the site.
4. If the work cannot avoid the roost, a licence is needed. In England that is a European protected species licence from Natural England, applied for with a survey and a method statement from a suitably qualified ecologist. It is not a same-week process.
5. The method changes, or the work waits. Often the answer is simple: leave that limb, cut in sections away from the feature, or return when the roost is not in use.

If a bat is found injured or grounded, do not handle it with bare hands and call the helpline.

Nesting birds

Separate law, similar effect. Under section 1 of the Wildlife and Countryside Act 1981 it is an offence to intentionally take, damage or destroy the nest of any wild bird while it is in use or being built. The protection is tied to the nest being active, not to a date, so an active nest in October is protected and an empty nest in May is generally not.

The main nesting season runs from March to August, with some species still nesting into September, which is why the RSPB advises hedge cutting between September and February. For tree work the rule is the same: between March and August a crew should check the crown before starting and keep checking as they go, and if an active nest is found, leave that section with a margin around it and return once the young have fledged. Hedge cutting and nesting season covers the detail, including the limited defence where damage is the incidental result of a lawful operation that could not reasonably have been avoided.

Other species that can stop or change a job

Great crested newts are also European protected species, with the same structure of offences including damage to a resting place. They matter for ground work rather than climbing: a pond, a damp corner, log piles, rubble and long grass near a breeding pond can all be newt habitat. If a clearance involves emptying a pond or lifting rubble and timber beside one, raise it.

Badgers are protected by the Protection of Badgers Act 1992, which makes it an offence to kill, injure or take a badger, to cruelly ill-treat one, or to interfere with a sett, including disturbing a badger occupying it. Sett interference needs a licence. Setts turn up at the bottom of large gardens backing onto railway embankments and woodland.

Hedgehogs are a different case. They are on Schedule 6 of the Wildlife and Countryside Act, which restricts certain methods of killing and taking, and the Wild Mammals (Protection) Act 1996 makes cruelty an offence. They are not on Schedule 5, so they lack the full protection bats have, and there is no legal requirement to survey for them before clearing a garden. What there is, is good practice, and it costs nothing: check log piles and the base of hedges by hand before strimming, lift rather than drag bonfire material, strim in stages from one side so animals can leave, and never strim blind into a dense pile. Most hedgehog injuries in gardens come from strimmers.

What it means for timing and cost

The honest position is that this can delay a job and occasionally add to it.

• Timing. Tree work with bat potential is best planned outside the maternity season, roughly June to August, and outside hibernation, roughly November to March, though the right window depends on the tree. Nesting birds push work towards September to February. Those two pressures overlap, which is why autumn is busy for tree surgeons. See best time of year for tree work.
• Cost. A visual habitat assessment by the contractor is usually part of the job. A survey by an ecologist, a climbing inspection or a licence application is a separate professional cost and is not on our price card, which covers the tree work itself, from £280 to £380 for a small removal up to £850 to £1,400 for a large one. Anything over £1,200, over 15 metres, over a road or near cables goes to a free survey.
• Emergency work. A genuinely dangerous tree still has to be dealt with, but wildlife law does not switch off. Do only what the danger requires, record why, and take advice on the rest.

Protected trees are a separate question. A Tree Preservation Order or a conservation area controls whether you may do the work at all, and wildlife law controls how and when. Both can apply to the same tree. See do I need permission to cut down a tree and trees in conservation areas.

Getting the work done

We are an introducer: we pass your enquiry to one vetted local tree surgeon who covers your area. When you book, say if the tree is mature, hollow, ivy-clad or has visible holes, and send photographs of the trunk and crown.

• Tree removal and tree felling
• Crown reduction and pollarding, which are often the alternative to removal
• Hedge removal, where nesting birds are the usual constraint
• Tree removal cost guide and crown reduction cost guide