by David Moore
Manager of Technical Services and Board Certified Entomologist
with contributions by Eric Smith, PhD, BCE
There are many ways that wildlife can get into our homes, but one that is often overlooked is the chimney. With the colder weather approaching, many of us will be using our chimneys more and potentially either allowing an animal into our homes or putting those animals at risk. We will review some of the animals that commonly come down a chimney, the risks they pose, and some ways to help prevent infestations.
(Credit: Humane Society)
Raccoons
Raccoons are commonly found throughout our service area, in both urban and rural segments. They will occasionally enter homes through chimneys in search of a denning site, especially female raccoons. Raccoons are a major host of rabies in the United States and can be very defensive if they feel threatened.
Bats
Bats are a common problem in chimneys, as they are capable of squeezing through very small spaces. Bats can carry rabies and other diseases, so any contact with them should be avoided. They also cause damage to the structure of the chimney over time due to their droppings and urine. Bats can readily come down a chimney if it has not been pest proofed. Bats are protected by law in most states, so it is important to check with wildlife services for any regulations before bat-proofing your home. The best time to bat-proof is the start of autumn, when bats begin hibernation.
(Credit: Humane Society)
Rodents
Mice, rats, and other rodents may also enter a chimney in search of a warm place to nest or food. These pests have the potential to bring in mites, ticks, fleas, and other parasites. Additionally, they can actually cause a blockage in your chimney. If they can manage their way into your home, they can create panic and potentially destroy your belongings or put your health at risk. Rodents bring with them the risk of disease and destruction of property. Unlike bats and birds, rodents do not need an open top to enter a chimney; they can squeeze through very small spaces. Rodents can be excluded at any time of year, but it is best done before the cold weather sets in and they seek a warm place to nest.
Birds
Birds are often found in chimneys, particularly those that have open tops. Birds such as sparrows and starlings may build nests in these areas, and they will defend their nest aggressively. As with bats, birds can carry diseases, so it is important to take steps to keep them out of your home. Bird-proofing is best done at the beginning of spring when the birds are nesting and can be excluded before they lay their eggs.
How To Prevent Pests from Entering Your Chimney
1. Install a Steel Mesh-Covered Chimney Cap. A chimney cap is the best way to keep animals out of your chimney. It will help keep debris, rain, and and other obstructuions from entering your chimney.
2. Seal All Potential Entry Points. The next step to prevent pests from entering your chimney is to make sure all potential entry points are sealed. This means checking around the base of the chimney, where it meets the roof, and any other places that could allow entry for animals. Caulk or expandable foam can be used to seal these areas if needed.
2. Ensure Fireplace Doors Remain Closed When Not in Use. By closing your fireplace doors, you reduce the risk of pests entering your chimney from inside.
4. Consider Hiring a Professional Chimney Sweep to Remove Nests or Dens. Having your chimney flue professionally cleaned on a regular basis will help remove any nests or debris that may be in the chimney, as well as ensure that it is safe to use.
Signs an Animal Is in Your Chimney — and What to Do
There are several signs that may indicate an animal is living in your chimney. These include:
- Scratching and scurrying noises coming from the fireplace or chimney
- A strong, foul odor of urine and/or feces coming from the fireplace or chimney
- Animal droppings on the floor near the fireplace or chimney
If a wild animal enters your chimney, the job should be left to professionals. They will know how to safely handle the animal and the situation to reduce risk to everyone around. A local chimney sweep, pest control company, or wildlife control professional can help you rid yourselves of these unwanted guests by performing a chimney inspection and developing a plan of action.
