Birds and Jackdaw Nests in Chimneys
Finding a bird's nest in your chimney is common in spring and summer, and jackdaws are usually the culprits. Their bulky twig nests block the draught, push smoke back into the room and pose a fire risk.
Why jackdaws love chimney pots
Jackdaws are crows and natural hole-nesters, so a chimney pot makes a near-perfect substitute for a tree cavity: sheltered, high up and hidden from predators. A pair often returns to the same chimney each year, dropping twigs until a nest forms that can fill much of the flue.
Signs of a nest in your chimney
Nests often go unnoticed until the room fills with smoke. Watch and listen for these tell-tale signs, especially from late winter to the end of summer.
| Sign | What it means |
|---|---|
| Scratching, flapping or calling sounds | A bird is active in the flue, often a jackdaw building or tending a nest. |
| Twigs and debris in the grate | Nesting material is falling down the flue, a strong indicator of building above. |
| Poor draught or smoke coming back into the room | The flue is partly or fully blocked, so smoke cannot escape properly. |
| A bad smell from the fireplace | Decaying material, droppings or, sadly, a trapped bird may be present. |
| Repeated bird activity around the pot | Jackdaws are establishing or returning to a nest site at the top of the chimney. |
The legal position on nesting birds
Under the Wildlife and Countryside Act 1981 it is an offence to intentionally take, damage or destroy the nest of a wild bird while it is in use or being built. An active nest with eggs or chicks must be left until the young have fledged, however inconvenient the blocked chimney. Old nests are normally cleared outside the breeding season, roughly outside February to August.
How a sweep removes an old nest safely
Clearing a nest is more involved than a routine sweep. The room is sheeted and sealed, then specialist rods and tools dislodge the tightly packed material with a HEPA vacuum managing the mess. A smoke test confirms the flue draws properly again. A responsible sweep checks first and only clears old, abandoned nests.
Preventing birds coming back
The best way to stop jackdaws returning is to fit a bird guard or cowl to the pot, letting smoke and gases out while keeping birds and debris out. It also helps with downdraughts and rain. Have it fitted by a professional straight after the nest is removed.