There are a few clues to look for in determining if bats are living in your house:
- If you have had two or more encounters with bats flying around your house within one calendar year, then you probably have bats.
- If you find piles of mouse like fecal matter in your attic or on the ground outside your house, then you probably have bats. Bats defecate before they enter your home and below where they roost for the day see. Make sure that the fecal matter is not old by laying down a piece of newspaper or cardboard and see if any more droppings fall on the paper. If there is, you have bats.
- You can distinguish between bat droppings and mouse droppings in two ways. First, bat droppings tend to be clustered as they will pile up below where the bat is roosting. Second, bat droppings will have a shiny speckled appearance (from all the insect wings) and will crumble like dust when touched. Mouse droppings on the other hand, tend to be scattered about and become hard when dry.
- Performing a bat watch at dusk is an ideal way of determining if you have bats. While it is not one hundred percent accurate, it is still worth doing. Perform a bat watch by having people stand by your house at dusk till dark. They should be positioned to see as much of the house as possible. The first person to see a bat should shout out. If you have trouble identifying the specific hole, concentrate on the side of the house where the first person saw the bat. Only perform bat watches on non-rainy nights.