Bat calendar

Like many other kinds of mammals, bats have a pattern that they follow during the year in terms of how they live. While this may deviate a bit depending upon the kind of bat you are talking about or the climate in that location, it is still quite common for the bat to follow a fairly routine schedule.

January – February - like bears, bats will hibernate during cold weather months even in areas on the globe where the temperatures are a bit warmer, like in Central America, the bat will choose to hibernate during these months. They will find a den where they can roost and spend the winter time upside down sleeping.

March - March can be a different kind of month for a bat depending upon the climate in which they are hibernating. If it is still cold during this month then they will most likely continue in their hibernation. However, if it is warmed up enough so that insects, especially flying insects, are available as a food source then you can be sure that the bats will awaken and be ready to start their year. It is really more the availability of food than the warm weather that becomes the determining factor.

April - April is the official month when all remaining bats will come out of their hibernation, referred to as torpor, and begin normal yearly processes. During this month, they will eat a great deal of food in an attempt to restore fat that has been lost during the winter hibernation. It is during this month that the male bats will begin to gather together to start to form groups, called bachelor colonies. This happens right near the end of April and will also be the time that breeding with the female bats will begin. As long as it is warm enough the females will accept the sperm and the fertilization process will begin. If it is not warm enough, then the males will inseminate the females, but they will store the sperm until it is warm enough and release it to the egg for fertilization at that time.

May – in this month, males and females will separate and the males will return to their bachelor colonies while the females start forming maternal colonies. Bats will frequently return to the exact same spots where they had bachelor and maternal colonies before.

June – in this month, the mothers will eat a great deal of insects to build up fat for the birthing process and for the care of their young. It takes a great deal of energy for a bat to care for the young. The gestation period is between 40 days and six months so some bats may have their babies during the month of June.

July – by this month, the vast majority of female bats will have had their babies. The pups are born naked and unable to care for themselves, so the mother bat must keep them warm and provide milk for nourishment. The nursing lasts about four weeks, which means that many bats will already be weaned long before this month comes to an end.

August – the baby bats will begin to fend for themselves during August and will see a rapid growth spurt over the next few months. The maternal colonies will begin to break apart during this month while the males remain in their bachelor colonies.

September – October – during these months the bats will start to prepare for hibernation again. They will begin to eat large amounts of food to build up excess fat and will look to find their places to roost for the winter.

November – December – in these final months of the year, the bats will return to their roosting place and begin to rest. There is really no food available to them for the most part, so it makes sense for them to begin the hibernation process again. NEED LOCAL HELP? We have wildlife removal professionals servicing 95% of the USA. Click here to hire a local bat removal expert in your home town. Updated 2018. It's best to be educated on the subject, so browse this site and especially read the bats in the attic home page, or email me if you have any more questions about Bat calendar

Wildlife Education - Information and Advice for the Safe Removal of Bats from Attics