My advice to you would be to call a professional in to humanely remove the bat for you- they can handle it safely and check to see if there is a roost up in your chimney. What you think is one bat might be several.
If it is a colony in your chimney, it’s summer and that means that there are probably mothers with babies that can’t fly yet. (In fact, there’s a real possibility that your confused brown bat is just a baby that has no idea what’s happening.) You might want to just shut the damper or secure the bottom of the chimney and wait for fall before getting them removed; that way you can ensure the babies will be all right.
If the bat is stuck in your house and flapping around in a panic, there are several steps you can take.
- Close off the room that the bat is in (towels under doors and everything). Put on gloves- leather or gardening gloves work fine- and long pants to reduce the risk of getting bitten.
- If the room has a window, open it, and see if the bat flies out naturally.
- If the bat doesn’t fly out, you can attempt to capture it using a small box or container after it lands. BE CAREFUL: bat wings are very delicate.
- Bats can’t take off well from the ground, so your best chances of catching it are when it is on the floor. Likewise, when releasing it, try to get it onto a tree or other vertical surface.
This video from Bat Conservation International might be helpful.
The thing is, your troubles aren’t going to be over once the bat is outside. That bat is going to go straight back to its roost in your chimney until you block it from coming back in. Which is why, again, I recommend calling a professional.
A warning: You should never ever ever attempt to pick up a wild bat with your bare hands. While people have a grossly exaggerated idea of how frequently they carry rabies (only about 0.5% of bats actually have it) it is nevertheless a virus you do NOT want to get. If a bat is being “docile” or having difficulty flying, that may be a symptom of the virus.
You can’t get rabies from bat poo, but there is a chance you could get a Histoplasmis fungal infection from poop that’s been left in damp conditions for a while. So be careful when cleaning up bat guano.
Ok, I think that’s about it. Good luck with your bat(s)!