A Bat's Calendar

Need bat removal in your hometown? We service over 500 USA locations! Click here to hire us in your town and check prices - updated for year 2020.

Bats, just like many other animals, particularly mammals, have a calendar, of sorts, that they stick to. This calendar will consist of different seasons, and different patterns of events, but that follow the same path at the same time each year. Different bats will have slightly different schedules from each other, and the timing may change a little from state to state, dependant on the climate. But, to get to the point, there is a kind of bat calendar, and if you have nuisance bats on your property, you’re going to need to know how it goes.

January & February

Some animals will hibernate throughout the winter, and bats are just one of those animals. January and February are usually still very cold months, meaning that bats, along with a wide range of other critters, won’t yet have woken up from their cold-weather slumber. It won’t be until the temperature increases, snow thaws, that kind of thing that the bats will come out to play. It is unlikely that you’ll see bats during the winter, unless you live in an area of quite warm climates, as they are very much a creature that struggles with low temperatures.


March usually indicates the start of spring and, therefore, the start of bats waking up from their hibernations. Of course, if the temperatures are still quite low, there still won’t be enough food around yet, making life quite difficult for bats. For some bats, and in some states, it might be early March that bats become active again, but for slighter cooler states, it could take a little longer, sometimes even into April.

March is generally the time of year that flowers bloom, which means that insects flourish, and it’s when the insects are in plentiful supplies that the bats will wake up. There is no point before there are insects in the air again, because they won’t find enough food to replace the energy they burn flying around.


Those bats that slept in late will have usually woken up by now, and they’ll be super active too. They’ll need to eat plenty to make up for the fat they would have lost during their winter hibernation. The males will often come together, forming a “bachelor group” of sorts, and as soon as the temperatures are favorable, the bats will start to mate. If the temperature is not high enough for the ladies yet, they’ll accept the male’s sperm, but they won’t use it yet. They store it, keeping it safe, until the temperatures rise, they feel the time is right, and they then fertilize their eggs using the previously accepted sperm.


Many female bats will be pregnant by this time, and they will start to come together, much in the same way that males come together to form bachelor groups. These new colonies of pregnant mothers will often contain many females together, classed as a maternity roost. The males and females do not stay together once mating has taken place. The males return to their bachelor groups, while females come together to support each other through pregnancy and rearing their young.


Again, the feeding frenzy will occur, but this time the females will eat much more. They’ll be eating for two, after all ... Usually, bats will only have one or two pups per litter. The gestation period will change from species to species, but can be as short as 35 to 40 days, or as long as six months. It is the larger species of bat that have the longest gestation periods.

Despite what you may have heard, bats are actually rather slow in reproducing, especially taking their size into consideration. When you look at how fast rodents such as mice and rats can procreate, bats seem almost tortoise-like in comparison. The thing with bats is that their babies can sometimes weight as much as 25 percent of their adult body weight. If you were to put that in the same terms as a human giving birth, it would be like a female giving birth to a child that was over 30 pound in weight. We’ll just give you a moment to let that sink in ...


Most of the bats that didn’t give birth in June will give birth in July. For around four to six weeks, the baby bats will be fur-less and totally incapable of taking care of themselves. At about the four week mark, however, most mothers would have weaned their youngsters, ready for them to get ready to live their life alone.


This is a very busy month for bats in the bat calendar, with many of the youngsters growing very quickly. They’ll start to leave the roosts, although female bats will sometimes stay in the same areas as their mothers, and when they have flown the nest, the mothers will start to break away from the maternity roosts. The males don’t follow the same path, choosing to stay together.

September & October

There isn’t really an easy time of the year for these flying mammals, with the fall seasons being the time to fatten up once again. This time, however, it isn’t preparing for breeding or recovering from hibernation weight loss, it’s to fatten up to prepare for hibernation instead. At the same time, the bats will also start to look for places to roost for the winter.

November & December

Most bats will have hibernated throughout these months, because they are too cold. Snow covers a lot, and the temperatures are so low that many insects aren’t out and about. Flowers die or close for the winter, making food very hard to come by. Water will freeze over. Shelter, especially warm shelter, is tough to find. Winter is a very difficult month for bats, and if they don’t migrate (which some do), they hibernate. If they didn’t do this, they would die.

And that’s the bat calendar. You will need to be aware of this information because it is unlawful to move or disturb bats at certain times of the year. They are protected, especially certain species of them, and you will not want to get yourself into trouble by trying to move these incorrectly, or at the wrong time of the year.

Go back to the Bat Removal page, or learn about bats in the attic with my Bats in the Attic guide.

Select Your Animal

RaccoonsRaccoon Removal Information & How-To Tips

SquirrelsSquirrel Removal Information & How-To Tips

OpossumOpossum Removal Information & How-To Tips

SkunksSkunk Removal Information & How-To Tips

RatsRat Removal Information & How-To Tips

MiceMouse Removal Information & How-To Tips

MolesMole Removal Information & How-To Tips

GroundhogGroundhog Removal Information & How-To Tips

ArmadillosArmadillo Removal Information & How-To Tips

BeaverBeaver Removal Information & How-To Tips

FoxFox Removal Information & How-To Tips

CoyotesCoyote Removal Information & How-To Tips

BirdsBird Removal Information & How-To Tips

BatsBat Removal Information & How-To Tips

SnakesSnake Removal Information & How-To Tips

DeadDead Animal Removal Information & How-To Tips

OthersOther Wildlife Species Information & How-To Tips