Bats in Homes in the Winter

BatDuring the winter many bats, especially Big Brown bats in Western New York hibernate in homes.   During mild weather, or when the home might be heated warmer than usual, the bats will wake up and search for food or water.  They often follow beams of light streaming in from lit rooms, thinking it is the way outside. It might be the light from a hallway, a tv or a reading light. These beams duplicate the light of dusk that bats use to find their way outside from attics during warmer months.

Many people are terrified of bats and they panic when they see one flying around their room at night. The bat is equally terrified – as he/she was planning on flying outside for a sip of water or a meal of insects. To send the bat out into the cold winter air is a death sentence for the bat, as is ignoring its need for water.  When bats wake from hibernation, their fat stores are rapidly depleted, often to the point where it will starve to death before spring. In addition, after three days of being awake and not getting water, the bat will become dehydrated and will perish.

Ideally, in this situation, the bat should be allowed to re-enter its state of hibernation after getting some food and water. This is not an easy process, as the bat needs to be kept awake long enough to be re-hydrated and replenish depleted fat stores with a special diet, then allowed time to digest the food and slowly re-enter the hibernative state.  But who will do this?  Not an easy, safe  or legal task for the average person who cares about bats. It is difficult to duplicate the conditions of a bat  hibernaculum. The temperature and humidity have to be just right. Years ago, some bats could be “overwintered” in refrigerators.  But with the new “frost free” refrigerators, all moisture is extracted from the bats body during the “frost free” process and the bats will die. Ideal conditions are those that are found in wine cellars.  Wine Humidors have been suggested, but since they are “air tight” the bats would suffocate.   Fox Wood is trying to find a solution to this dilemma so that we can help more bats.

There are precious few people who understand bat biology, and even fewer in New York State. With White-Nose Syndrome decimating our Little Brown bat populations, there is a possibility that this disease could spread to our Big Brown Bats- and what will be the costs to the environment and  humans as a result of the loss of these bats?  Insect populations would spiral out of control,  pesticide use would have to be accelerated and that’s not going to be a good situation.

Please be kind to bats.  If you know there are a few hibernating in your attic, please allow them to stay at least until spring.  Use caulk to seal off cracks and holes that might allow them into your living space.  If you need to have them removed, please wait until spring and hire a reputable, environmentally conscious Bat Excluder to install one-way doors and check valves after insuring all cracks and holes where the bats may re-enter are sealed or repaired.  In New york, the rule of thumb is “June or July, let ’em fly”.  This means that the bats have their young in the very beginning of June, and so you will need to have them excluded before June, and wait until at least the second week in August when their young can fly to attempt an exclusion.   If you have bats in your home that you don’t want, then you need to take a close look at your home.  If you have bats getting in, you also have bees getting in, and warm air escaping in the winter. Many bat excluders are experienced carpenters who can advise you on necessary repairs.