Pest Control
Chimney nests and uninvited guests: a closer look at the jackdaw
Sticks in the fireplace and a noisy chimney in spring usually mean jackdaws. Why a chimney nest is a real hazard, what the law allows, and how to keep them out.
Jackdaws love chimneys. A pair can fill a flue with sticks in a matter of days, and the first a household knows of it is often twigs in the grate or a fire that will not draw. A chimney nest is more than a nuisance, and there are rules about what can be done and when.
The short version
- A nest in a flue can block it, causing a fire risk and carbon monoxide risk if the fire or stove is used.
- Jackdaws are protected under the Wildlife and Countryside Act 1981. An active nest must not be disturbed.
- A cowl or bird guard fitted outside the nesting season is the reliable fix.
What does a jackdaw look like?
Jackdaws (Corvus monedula) are the smallest common member of the crow family in Britain, about 33 to 34cm long. They are black with a grey nape and sides of the neck, like a shawl, a short stout bill and a distinctive pale eye. They are sociable, noisy birds with a short, sharp "chack" call, and they nest in holes: in trees, cliffs, old buildings and, very often, chimneys.
They are clever, adaptable birds that will raid feeders and take eggs and chicks from other birds' nests, which is why they are not always popular in gardens.
I think jackdaws are nesting in my chimney. Should I be worried?
Signs include sticks, twigs and nesting material falling into the fireplace, birds going in and out of the chimney pot in spring, and scratching, calling or the cheeping of chicks in the stack. A jackdaw nest in a flue is worth taking seriously:
- Blocked flue. Jackdaws drop sticks into a chimney until they wedge, then build on top. The result can block the flue completely, so smoke and fumes cannot escape. Burning a fire or using a stove under a blocked flue risks carbon monoxide poisoning, which can be fatal.
- Fire risk. Dry sticks and nesting material can catch light from hot flue gases and cause a chimney fire.
- Noise and mess. Calling and chicks in the stack can carry into the room, and debris falls into the grate.
If you suspect a nest, do not light a fire or use a stove on that flue until it has been checked and cleared. Make sure you have a working carbon monoxide alarm in any room with a fuel-burning appliance.
What should I do if I discover jackdaws nesting in my chimney?
All wild birds, their nests and eggs are protected under the Wildlife and Countryside Act 1981. It is an offence to take, damage or destroy the nest of a wild bird while it is in use or being built, or to take or destroy its eggs. In practice that means a nest with eggs or chicks in it has to be left until the young have fledged, usually by early summer, and the flue left unused until then.
Once the nest is no longer in use, it can be cleared. A chimney sweep is often the right first call for clearing the flue itself, and many will also fit a guard. Clearing a chimney from the roof is work at height and should not be attempted from a ladder.
How to stop jackdaws coming back
Jackdaws return to the same site year after year, so clearing the nest without proofing the chimney usually means the same problem next spring. The options are:
- A cowl or bird guard on the chimney pot, which lets smoke and gases out but keeps birds from getting in. This is the reliable long-term fix for a chimney that is in use.
- Capping the chimney, if the fireplace is no longer used. The cap should still allow some ventilation to prevent damp in the stack.
- Regular sweeping of a flue that is in use, which also clears any early nesting material.
Proofing work should be done outside the nesting season, roughly late summer through winter, so that no active nest is disturbed. Scaring devices such as balloons and kites rarely work for long against jackdaws, which quickly learn they are harmless.
When to call us
If jackdaws are nesting in your chimney or roof, we can confirm what is there, advise on timing under the law, and arrange proofing once the nest is no longer active. Where a sweep is the better first call, we will say so.
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Send us a photo or describe it. We will tell you what it is, whether it needs treating at all, and what it would cost, before anyone comes out.