Bird nests with or without birds in them are a health and fire safety problem for your home. Bird droppings are not only unsightly in your fireplace, but birds can also carry mites and parasites into you home.
One note: In both the United States and the United Kingdom, active nests with birds or eggs in them are legally protected from being disturbed or destroyed. Chimney swallows, for example, are classified as protected birds by the federal government.
How to Get Rid of Bird Nests in Chimney
For both legal and humane reasons, wait until the nestlings are gone before removing any nest.
Keep your fireplace damper and, if you have them, fireplace glass doors, closed if there is an active nest in your chimney. Do not light a fire. Be aware, for example, that barn swallows, which are one of the most common birds to nest in home chimneys, hatch in 15 days. The young continue to use the nest for up to three weeks. Typically, a second brood is hatched while the first brood is still using the nest. The older siblings help feed the new baby birds. You will recognize barn swallows by their characteristic forked tail. Barn swallow nests you can recognize by their cone or pocket shaped mud nest plastered to the vertical wall of your chimney.
A choice is whether to do it yourself or bring in a chimney sweep to remove inactive bird nests from a chimney. Some bird nests can be easily removed by any homeowner willing to go up on the roof. Others, such as barn swallow nests, require scraping the nest from the interior of the chimney. This is a messy process that can drop unsanitary and possibly mite-infested material into your fireplace. (See Dangers of Bird Droppings in Chimneys.) If you do this type of bird nest removal yourself, we suggest you take your shop-vac to the roof and use it to catch bird nest debris as you remove it.
Whether you remove the bird nest yourself or hire a chimney sweep to do it, it is imperative to remove any nests or remaining nesting materials before using your fireplace in the fall. Combustible material inside your chimney flue and a burning fire are not a good combination!
Are You Ready to Prevent Bird Nests in Your Chimney?
But bird nests in chimney need not be an annual concern. A damper that seals the top of your chimney , such as a Lyemance damper, can prevent any animal, including birds, from using your chimney for shelter or nesting purposes. You can open such a chimney damper when you have a fireplace fire.
See How to Prevent Birds and Bird Nests in Your Chimney.