From late fall bats prepare for hibernation storing the fat reserves they will need to last until spring. In Michigan there is a shortage of food for insectivorous animals. Bats will either migrate to warmer climates or go into hibernation. Most male brown bats in Michigan will choose hibernation, most of the time this will be a big brown bat. Hibernating bats require temperatures to be 45 degrees or above. Summer nurseries or maternity colonies need temperatures close to 70 degrees or above therefore they will not hibernate in Michigan. A bat will drop its heartbeat from 400 beats per minute when active to 25 beats per minute when in hibernation. Even in hibernation, a bat must periodically arouse to drink or urinate, or sometimes find a warmer spot within the dwelling area as temperature fluctuates. Moisture on the walls or condensation on their fur provides drinking water during this time. A brown bat may awake every 12-19 days, but could stay in hibernation for up to 83 days. As the winter goes on, the fat a bat has stored during fall is slowly metabolized. These limited reserves must last it anywhere from five to eight months. When winter temperatures rise above 55 degrees bats will arouse and feed, often in the brief warmth of mid-afternoon, in order to capture the few available insects.
Questions we often hear during the winter months in Michigan:
A short answer is you can’t. Well not completely. Most bats in the attic in Michigan live beneath the insulation or in wall cavities where it’s warm. Some bats in the attic can be removed and relocated by hand. Not all bats are ever found in any certain attic.
The bat removal process in the winter is a 3 step process:
- Inspection: Locating entry points and other potential entry points.
- Live Bat Exclusion: Installing one way doors and bat proofing the rest of the home.
- Return visit: Re-inspect the home and remove one way door devices during the spring.
The length of time it takes bats to exit your home varies depending on the season. During summer months, getting rid of bats usually takes between one and three days. During winter, or other times of extreme cold, bats often hibernate and have very low activity levels. Getting rid of bats during these seasons may take several weeks or months.
Improper Bat Removal Techniques
The process mentioned above is the only acceptable way to get rid of bats from homes and attics. Glue boards, “Bat-A-Way”, or high frequency noise emitters are gimmicks and unacceptable ways to solve a bat problem. The Federal Trade Commission has provided a ban against the selling ultrasonic pest control devices. There are no poisons, pesticides or fumigations you can use to evict bats from your home. Bats are both state and federally protected species here in Michigan. Because of White Nose Syndrome (WNS) bats are now on the endangered list. Also because of West Nile and other various diseases bats are great to control the insect population and prevent the spread of diseases. Fines for killing bats in Michigan can be up to $5,000.
Bats are a beneficial species. They are an important part of any local ecosystem, with some species eating significant numbers of potential agricultural pests such as mosquitos, beetles and moths. Like all wildlife in Michigan, bats can carry rabies. Human rabies cases are rare in the U.S., with an average of 2-3 cases documented each year. It is estimated that in the U.S., 40,000 people each year receive rabies post-exposure and many of these following an exposure to bats. Some of these treatments can be avoided if the bat can be collected and tested for rabies. If the animal tests negative for rabies, no treatment is necessary.
Bat removal, bat control and bat relocation during the Winter months can often be the best time to exclude bats. If your roofs are clear of snow and ice we can get to all of the entry points and potential entry points. We can perform all of the necessary repairs to exclude the colony of bats. The temperature is generally too cold for the bats to fly, but Michigan weather is so inconsistent sometimes it warms up enough for them to fly. Exclusion devices are left up until the end of spring to ensure any bats in the roost will be excluded.
Bats move with temperature change and if they become dehydrated. Typically every 12-19 days bats will search your attic and walls for water. During this a bat will mistakenly end up in the your bedroom, living quarters, or basement. A bat during the winter can survive on condensation in the attic and walls.
Most likely no. Bats that enter your home during the winter typically mean the bats were hibernating in your attic space. Bats are not very active on the outside of your home during cold winter months. They did not fly in your house when you left the garage door open. They found an opening from the attic or a wall.
Most importantly you have to be patient. Bats living in your attic over the winter are not going to leave over night. It may take months for the bats to leave your home. Bats that enter your home during this time may be very disoriented and are simply looking for a way out. If you find a bat flying in your house open a window or door. The bat may fly out within a few short minutes. If you can not get rid of the bat from your house, it may be time to call a professional.
Not all attics need to be clean out, but many do. The winter or colder months are the best times to clean out the attic. We can often times remove hibernating bats located underneath insulation while we remove the insulation. During your home inspection we will look in the attic and determine if you need attic restoration work.