Living with urban wildlife
Big Brown Bat
Bats are perhaps one of the most misunderstood animals we share our environment with. Contrary to popular myths, bats present very little danger to humans and in fact are extremely beneficial as a form of natural insect control. One bat can consume thousands of mosquitoes and other flying insects each might. Bats are inconspicuous, nocturnal flying mammals that usually cause conflicts only when selecting roosting sites.
Bats use two types of roosts – night roosts, which are trees where they rest between feeding forays and which are not a problem, and permanent roosts where they sleep during the day, where they raise their young, and where they hibernate.
These permanent roosts can be in cracks and crevices in the attic or under the eaves of your home and are often identified by droppings around the openings to these sites. To prevent the mess created by bat guano (fecal droppings), exclude the bats from these roosting sites by filling all the entrance holes. This can be quite a challenge since bats can squeeze though openings as small as 3/8-inch wide.
Do not block off openings during the summer months because you may trap babies inside. Likewise, do not block off openings during the winter months when the bats are hibernating or in early spring before babies are born.
During safe times of year, holes should be sealed only after it is dark and the bats are out feeding; otherwise, they may be trapped inside where they will starve to death. Do not use repellents because the bats will only move farther into the building.
For the homeowner who appreciates the ecological benefits of having bats around, bat roosting boxes can be built and placed near your home. If a bat inadvertently enters your house, remain calm and provide it with an exit route, such as an open window or door. Since bats are nocturnal, you may have to wait until it is dark before the bat will find the exit.
We do not recommend handling any bat. If you choose to do so, wear protective gloves and cover the animal with a towel. Never handle a bat with bare hands. Although uncommon, there have been documented cases of rabies in Oregon bats.
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