Some people love watching birds and squirrels in the back yard. Others like animals well enough but curse the squirrel raiding the bird feeder. And some would rather have nothing to do with them at all. Whichever camp you're in, nobody wants those animals inside their chimney — which is where a chimney cap earns its keep.
How They Get In
Most chimney caps include wire netting around the sides to block animals. If yours doesn't have one, or the netting has been damaged, something will eventually find its way down. It usually happens in warmer months when the chimney isn't in use.
Your chimney damper is the second line of defence. If it's closed and sealing properly, the animal can't get further into the house. Be aware that larger animals like raccoons can force certain damper designs open if they're determined enough.
Squirrels and Other Small Animals
If you hear scuffling in the chimney, deal with it quickly. Small animals often end up trapped in a metal liner by accident — once they fall or climb down, there's nothing for their claws to grip, so they can't get back out.
The fix is to give them a route. Feed a length of thick rope down the chimney liner and secure it at the top, then wait. In most cases the animal climbs out on its own. Once you're certain it's gone and the noise has stopped, fit a chimney cap with wire netting so it doesn't happen again.
Raccoons
Raccoons are a different problem. They're large enough to brace against the flue and climb in and out freely, which means a raccoon in your chimney usually means a nest — often with babies.
Odour deterrents such as predator urine can work, though you'll be living with the smell too. There are also traps designed to catch an animal as it exits the liner. Once the mother is caught you can usually reach up through the fireplace to remove the babies and nest, which will typically be sitting on the smoke shelf. Alternatively, scare the mother out, retrieve the babies, and use them as bait in a live trap.
Check your local laws first. Trapping raccoons is illegal in some areas.
Bats
Bats are common in chimneys for obvious reasons — dark, sheltered, and the tight space they feel safe in. If you suspect bats, call a bat removal specialist rather than handling it yourself.
Extermination is the wrong approach here. Bats are small and extremely hard to spot in a dark flue, and any you miss create a worse problem than the one you started with. A specialist will remove them properly.
The Bottom Line
Whatever has moved in, getting it out should be the first thing on your list. If you hear movement in the chimney, make sure the damper is closed and secure — otherwise a chimney problem becomes a house problem.
If you'd rather not handle it, call a pest removal expert. They'll have traps designed specifically for chimneys and removal methods you won't. Once the animal is out, fit a proper chimney cap to keep the next one from getting in.