Maternity colonies that occupy bat houses sometimes encounter problems during the summer months, including overheating and overcrowding.
Baby bats need very warm temperatures in order to maintain their growth rate, however, bat houses occasionally overheat during the summer months, causing both pups and mother bats to fall out. These bats are in a weakened state from heat exhaustion and often die. The added warmth of the summer, coupled with the fact that the population in a bat house will double as the young are born and growing, can result in disastrous consequences for the colony.
These bats can be helped by installing a net below the bat house that enables the bats to grab on if they are falling and allow them to climb back to the house. When temperatures are extreme, the bats may also be able to move out of the bat house and onto the net to cool themselves.
Please note that grounded bats should never be rescued with bare hands. See our Locate a Rescuer page for information on how to safely contain bats in trouble, as well as a state-by-state list of bat rescuers.
Materials Needed to build a pup-catcher:
- 24″ length of nylon window screen or plastic “bat house” mesh.
- Two short-length of scrap wood
- Staple gun and staples
- Zip ties
The pup catcher must extend at least 24 inches below the opening of the bat house in order to prevent interference with bats exiting and entering the bat house. Cut the net so that it is the same width of your bat house and at least 24″ long. Cut two sections of wood the same width as your bat house. Staple one end of the length of screen to one of wood pieces (#1).
Use screws to mount both sections of wood to the pole or other surface on which the bat house is mounted.
Note: If nylon screen is used, guano may collect in the pouch requiring it to be gently hosed or cleaned out. The plastic mesh recommended above has holes large enough to allow most guano pellets to fall through or be naturally washed out with rain. The plastic mesh is also UV resistant. (Special thanks to Stephanie Ann for providing these photos.)