There are so many myths surrounding bats that the first thing to do is to dispel these:
- Bats are not blind. They use a form of "radar" to navigate, but can see as well as humans.
- As a general rule, bats do not attack people or get tangled in their hair.
- Although Vampire bats do exist, they live only in Latin America and feed only on the blood of livestock or birds.
That said, bats can cause problems in homes or buildings:
- An accumulation of their droppings can cause Histoplasmosis, attract insects or other bats, and can leave persistent odor. Their scratching and squeaking can be annoying. Although most bats do not have rabies, like most wildlife, there is the possibility that one does and would pass the disease if a person is bitten.
Bats may enter homes and buildings during any season:
- Winter - enter seeking a warm place to overwinter. Some species tend to hibernate individually, others will enter warm homes or buildings in small groups to wait out the winter. They may become active if the attic or other area in which they are hibernating becomes excessively cold or hot.
- Spring - females enter as they prepare to give birth. The babies are then born in early to mid-summer.
- Summer - during summer bats will harbor in buildings to raise their young. Although they roost in homes and buildings both winter and summer, they will often move between seasons to different structures.
- Fall - males will join females to begin mating.
Bats are most often found inhabiting buildings that are near water and food sources, such as ponds, lakes or streams and other areas with high moisture and high insect populations.
Because bat infestations can cause lingering odors, new populations may be attracted to buildings where bats have previously harbored.
They are also attracted to warm structures in which to raise their young.
The easiest way to inspect for bats is to watch the upper area of the home at dusk. They will begin leaving their harborage to feed anytime within about an hour before and after the sun sets.
If the home or building is large, it can be advantageous to have several people watching different areas.
Inside the building, look for dead or live bats and bat droppings. Bats generally seek out concealed areas within the roof or ceiling, or more exposed but out-of-the-way places in rafters.
Bat Prevention and Control
As with most pests, the best prevention is bat-proofing your home; that is, sealing all possible openings through which the bats could enter. For bats, this is also the best method of control
- Bats can enter through openings as small as 3/8 inch. In most cases they will enter at high points, but they may also enter through open doors, such as those of garages, sheds or barns.
- Where possible and practical, seal potential entry points with caulk or hardening foams.
- Vents and other needed openings can also be sealed with netting or wire screens.
When sealing a structure, care should be taken to not seal bats in. To prevent that:
- It is best to seal the home in late fall or early spring, after populations have left and before new bats enter.
- To exclude an existing population, Purdue University recommends:
- Seal all but one or two of the main openings. Wait 3-4 days for the bats to adjust
- Install a one-way exit, placing a mesh-screen cloth funnel over remaining openings.
- Permanently seal openings once bat activity ceases.
- However, summer control is not recommended. Because bat babies are born and raised during summer months, control attempted at this time could end up sealing in the babies.
Bats may also be repelled by direct drafts or breezes of cold air from air conditioning or fans in the area they seek to roost in the spring, as they are desire warm locations to raise their young. Bats may also be repelled by bright lights in areas they seek to harbor.