How to remove bats from the home, humanely and with a zero kill rate
First, let’s talk about the window of opportunity. If you have a colony of bats in your home the most important thing to keep in mind is these are female bats with young. April through August is the maternity phase of bats. This is not the time to attempt removal. September is the perfect time frame for removal. Any earlier and you risk killing juveniles. Waiting later than mid-October, depending on your climate zone, and you risk freezing already pregnant bats. They need time to find a suitable place to hibernate.
The second thing to know is, bats are extremely beneficial to humans. So a no-kill approach is not only ethical and humane, it is the law in nearly every State in the Union.
The third thing we need to realize, poisons and repellents are not effective. Bats eat live insects. Poisonous pellets are not on a bats menu. Repellents are largely useless as well. Bats do not care if their warm cozy home is smelly or noisy.
This leaves the homeowner with one viable alternative. Exclusion. Exclusion is like trapping in reverse. It allows the animal to leave but not return. It traps the wildlife outside.
The place to start with removal is to find all the points of entry. This can be done by watching the home at dusk to see where the bats are leaving. You can also look for droppings concentrated in areas around the exterior of your home.
After locating all the entrance and exit holes or cracks, seal all but one with a polyurethane caulk. A crack or hole only needs to be as big as a nickel for a bat to pass through. If it is a large area, a 1/16 inch mesh can be applied. After all but one entry points have been sealed, a trap with a one-way door can be used to cover the last entry point. There are metal traps, as well as a plastic cone that is easily stapled, nailed or taped over the opening. The bats come out, but can not get back in. There is no need to flush or shew the animals out. They leave on their own every night. Keep in mind, they leave and return in shifts.
The first nightly exodus is just the first wave. You can leave the trap in place for several nights to make sure any sick or wounded bats have had a chance to recuperate and are ready to get back to cleaning up the mosquitoes around your home. When you are sure they are all gone, simply seal the last entry and your home is nearly back to being your sanctuary.
A bat house can be bought or built and placed in your back yard. This will give the colony a place to go and keep the little gals close to work on your insect problems around your outside spaces.