Birds Nesting in Your Chimney: What Can You Do?

Wildlife law makes it an offence to intentionally damage, destroy or remove a wild bird's nest during its building or use, at the top of a flue as much as in a hedge.

The practical meaning is simple. A nest with eggs, chicks or adults still using it is off limits. A nest from a previous year that nothing is using is not covered in the same way. The difficulty is knowing which one you have, because a chimney is dark and deep, and you cannot always see inside from the hearth.

GOV.UK's guidance on wild birds also notes there are no licensing purposes that permit development or construction. In plain terms, wanting to get a roof job finished is not a reason to disturb an active nest, and a roofer cannot be given a licence to do it for you.

Birds nest when they choose and the timing varies, so a calendar is no guide. What counts is whether anything is using the nest now. If in doubt, leave it alone and ask for advice.

Our answer on bats and nesting birds in the roof covers the wider position.

You may hear scratching, fluttering or a chirping noise from the fireplace, particularly in the morning. Twigs, straw or soot-covered debris can drop into the grate, and a dull, flapping sound sometimes comes down the flue on a windy day. Birds going in and out of the pot above are the clearest sign of all.

A blocked flue is a safety problem as well as a wildlife one. If the fire is lit, smoke and fumes can be pushed back into the room instead of up the stack. Do not light a fire or a stove while you suspect a nest, and never try to burn it out. If you have a gas fire, the same applies. Turn it off if you smell fumes or feel unwell, and get fresh air.

Check from outside, from the garden, using binoculars if you have them. Watching for ten minutes can show whether birds are coming and going with food. Do not lean a ladder against the stack to look.

If a nest is clearly active, wait. A short delay is better than an offence. Our guide on calling a sweep or a roofer explains who suits which chimney problem.

Jackdaws are small crows that readily use old chimneys. They carry sticks to the top of an open pot and drop them down, and the sticks wedge across the flue and pile up in a bulky mass. A nest can grow into a plug that fills a good length of the flue, and unlike a small songbird's nest it is hard to remove with a brush.

Because the stack is tall and the flue is narrow, a jackdaw nest also holds moisture, which can lead to damp patches on the chimney breast.

The same rule holds, though: if the nest is in use, it is protected. Clearing a big nest is also a job for a competent person, since a sweep or a roofer working from a safe platform can see and clear what a householder cannot. A stack that has been blocked for several seasons may also need the pot, flaunching and flashing checked for damage afterwards.

A disused chimney is the common target. If you are not using the fireplace at all, a cap with ventilation is often the better answer, and our guide on capping a disused chimney describes how that is done.

Once a nest is empty and unused, the answer is to remove it and stop birds coming back. A guard or cowl sits on top of the pot, letting smoke leave while keeping out birds, leaves and a good deal of rain. A wire cage suits an open flue; a cowl with a solid hood also helps with downdraught. The right choice depends on whether the fireplace is in use. Our guide to chimney pots and cowls compares the types.

Fit the guard only when the pot is clear and nothing is nesting in it. A guard fitted over an active nest could trap young birds and would put you on the wrong side of the law. If you use an open fire or stove, the guard should be sized so it does not choke the flue.

Call a chimney sweep to clear the flue and a roofer for the work at the top of the stack, such as the guard, the pot or the flaunching. We can inspect from a safe platform, tell you what is in the pot and quote one written total for the clearance, the guard and any repair the survey shows is needed.

See our chimney repairs page for the work we cover.