Because of bat lore and myths and because they are only active at night, bats are often misunderstood and maligned. They are not blind nor dirty. They do not get caught in people's hair or infest homes with bedbugs. Like other mammals, less than 1% contract rabies. Most bats are harmless and highly beneficial for insect control. They are the only major predator of night-flying insects. They pollinate fruit flowers. They are valuable in medical research and are an important source of fertilizer (bat guano is actually mined from caves). Bats are fascinating to watch and learn about.
What Kinds of Bats Use Bat Houses?
Throughout the northern two-thirds of the U.S. and Canada, the Little Brown Bat (Myotis lucifugus) and the Big Brown Bat (Eptesicus fuscus) can be found using bat houses. Any bats that roost in crevises or can be found under bridges and in buildings are likely tenants for bat houses.
Do Bats Live in a House All Year Round or Do They Migrate in the Winter?
In the northern two-thirds of the U.S. and Canada, most bats migrate south in the Winter. Very few species can survive northern subfreezing temperatures. Bats that inhabit bat houses generally move to an isolated cave or abandoned mine, while tree roosting bats travel south just like birds. Bats might Winter over in bat houses if they are in the southernmost area of the northern section. Also, the Big Brown Bat can Winter over because of its hardiness.
How Do You Attract Bats to Your Bat House?
Bats find bat houses just like birds find birdhouses. If a house is in the proper location, meets the bats' requirements and is needed, bats will move in on their own.
How Can I Determine if I Will Get Bats in my House?
Bats like a source of water (streams, marshes and lakes) and an area plentiful with insects. They will travel up to a mile or more to water sources. Established older urban areas with large trees and landscaped yards near water can provide bat habitats.
How Can I Determine if Bats Live in my Area?
Watch for them at dusk or around street lights at night. You will see them silently soaring and diving. You might also check with a local nature center or pest control company to see if they have received sightings. If you want to have some fun, bat detectors are available from various sources and can be tuned to listen to the echo-locating calls of bats as they feed at night. They can be heard from 30 to 100 feet away, depending on the species.
Can Bats Be Introduced Into Areas Where they Do Not Live?
If you put up a bat house, you could probably attract a traveling bat species and provide them a home in your yard. But, you cannot artificially introduce bats because their homing instincts would cause them to leave immediately.
Can I Get Bats in my House to Move into a Bat House?
Bats (especially nursery colonies) like attics because of the stable high temperatures and the option to move vertically to select from a range of temperatures under varied weather conditions. Colonies of bachelors tend to like cooler roosts. A bat house will not lure bats out of a good attic. If you exclude them from the attic, they have fewer options for roosting and may move into the house.
When Should I Hang a Bat House and When Will Bats Move In?
Bat houses can be hung anytime, but Fall, Winter or early Spring is preferred. It typically takes a year to a year and a half to attract bats, although some people report occupancy in only a few hours.
How Should I Mount my Bat House?
Since appropriate temperatures determine whether a house is used, consider geographic factors.
Can the Bat House Be Protected from Predators?
Take the same precautions you would take with a birdhouse. Houses hung on the sides of buildings are probably safest from predators and are preferred by bats. No bottom in the bat house prevents competition from birds and other animals such as mice and squirrels.
Is it Safe to Observe the Bats Roosting in the Bat House?
You can carefully observe your bats. The longer they reside in your house, the more tolerant they are. If you think you have a nursery colony, you can shine a flashlight inside soon after the mothers leave at dusk in June or early July. Do this only at short intervals and not more than once a week. Young are left behind in the roost for the first three to four weeks. If you disturb the roost too much, they may abandon the house.
If you would like to register your bat house for research purposes, contact The Organization for Bat Conservation at (517) 655-9200.
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