Animals in Your Chimney: Birds, Squirrels, Raccoons, and What NJ Sweeps Actually Do

Chimney animal calls make up roughly 8% of our spring and early-summer service load in New Jersey. Every one of them is a two-part problem: get the animal out safely and legally, then close the entry point so the next one does not move in. Here is how each species is different, and what New Jersey law actually permits.

Chimney swifts (federally protected, cannot be removed)

Chimney swifts are small, insect-eating migratory birds that nest exclusively in vertical hollow structures, historically hollow trees, now almost exclusively chimneys. They arrive in NJ in early May, nest through late July, and depart by early September. During the nesting period they are protected under the federal Migratory Bird Treaty Act and it is illegal to remove them, their nests, their eggs, or their young.

If you have chimney swifts, you have them until September. Do not light a fire. Do not attempt removal. The good news: swifts eat their weight in mosquitoes daily, do no structural damage, and leave on their own. Once they are gone, install a stainless mesh cap (5/8-inch openings or smaller) to prevent them from nesting again next year.

Squirrels (the most common call)

Gray squirrels enter open chimneys looking for a warm, dry nest site and then discover they cannot climb out of a smooth clay flue. They will scratch, chirp, and eventually die in the chimney if not removed. Removal is legal year-round in NJ for gray squirrels.

The standard humane removal: lower a heavy rope down the flue with knots tied every 12 inches. The squirrel climbs the rope out. This works about 80% of the time and takes 4 to 24 hours. If the rope method fails, we come out with a live-trap that mounts to the flue opening at the top.

Cost: $175 to $350 for a service call, plus cap installation ($249 to $450) which is essentially mandatory to prevent immediate re-entry by another squirrel.

Raccoons (the highest-effort call)

Female raccoons occasionally use chimneys as birthing dens in April: May. This is the most difficult chimney-animal scenario: a 20-pound protective mother with 3 to 5 kits, all of which need to be removed alive and relocated per NJ Fish & Wildlife regulations.

Do not light a fire under a raccoon. Do not attempt to smoke or wash them out. Do not drop anything down on them. Call a licensed wildlife control operator (NJ DEP maintains a list) plus a chimney sweep for the post-removal cleanup and cap install. Combined cost typically $600 to $1,500 depending on how long they have been in place and how much damage the mother did to the damper trying to escape.

European starlings and house sparrows (invasive, no protection)

Both species are non-native and not protected under federal law. Nests can be legally removed at any time. The problem is usually nest material, starlings pack impressive volumes of grass, twigs, and trash into a flue and can completely block draft in a few weeks. If you smell a musty, ammonia-like odor from the fireplace in spring, check for starling nesting immediately.

Chimney bats

Uncommon but not impossible. NJ has 9 native bat species, several of which are state-threatened or endangered due to white-nose syndrome. If bats are roosting in your chimney, do not attempt removal, call a licensed wildlife control operator experienced with bat exclusion. Sealing them in during roosting season kills them; sealing them in during maternity season kills the young, which is illegal and creates a decomposition problem in the flue.

The permanent fix

Every chimney in New Jersey should have a stainless steel cap with 5/8-inch mesh screen on every flue. This is the single most effective animal-exclusion measure available and it is not expensive. Aluminum caps corrode; galvanized caps rust; only stainless holds up long-term, especially in Shore counties.

If your chimney has ever had an animal in it, or if your cap is more than 15 years old, that is the fix. $249 to $500 installed, and it eliminates 95% of future animal calls.