The size of your bat house matters: Here's why
August 31 2022 – Harrison Broadhurst
From size, to quality, to location, there are many factors that influence bat house success.
One often overlooked but crucially important factor for bat house success is their size. The size of your bat house does a lot more than determine how many bats can fit inside.
THE SIZE OF YOUR BAT HOUSES CAN MAKE OR BREAK YOUR BAT HOUSE’S SUCCESS.
Let’s talk about why.
WHY DOES BAT HOUSE SIZE MATTER?
It has to do with heat retention.
TALLER BAT HOUSES WITH MULTIPLE CHAMBERS AND VENTS BEST PROVIDE A RANGE OF TEMPERATURES THAT ARE NEEDED BY THE BATS.
As the sun hits the bat house, the warm air rises and is caught at the top of the bat house, increasing the temperature. The lower area of the bat house on the other hand, especially below vents, remains cool.
BatBnBs also have vents near the base to allow for more airflow. These vents allow bats to escape extra high temperatures.
Having a range of temperature is crucially important for bats: especially for nursery colonies. They need the warm temperatures, but it can become too hot at the peak of summer at noon, so it’s important to give them the option to move to a cooler zone, without leaving the safety of the house.
THE TEMPERATURE CREATED IN MULTI-CHAMBERED BAT HOUSES ALLOWS BATS TO CHOOSE AMONG A WIDER RANGE OF TEMPERATURE, PERMITTING ADJUSTMENT TO HOT VERSUS COOL DAYS.
BatBnBs also have a hole built in between the multiple chambers to allow for the bats to easily and safely move from one to the other.
EXPERTS RECOMMEND LARGER BAT BOXES:
Leading bat conservation organizations, Merlin Tuttle's Bat Conservation (MTBC) & Bat Conservation International (BCI) both recommend that bat house roosting chambers should be 20” or more tall; and more is better. (MTBC, BCI)
Here are the dimensions of BatBnB’s single-chambered and dual-chambered BatBnBs to give them the best chance of success:
Bat expert Dr. Merlin Tuttle reports that bat houses such as BatBnBs can expect up to an 80% success rate when properly located, due to their bat-friendly design.
DON’T LET THE SIZE INTIMIDATE YOU
It’s understandable that some people are initially surprised by how large BatBnBs are, but don’t be discouraged: the included quick-mounting system makes BatBnBs easy and safe to hang.
Additionally, bigger bat houses also make excellent conversation starters. It can serve as a catalyst to help more people understand the importance of these mosquito-munching, misunderstood mammals.
Are you ready to get your own bat house? See the different models here!
Bat houses should get around 6 or more hours of sunlight throughout the day. That is important, because bats like to stay warm during the day, especially if there are pups involved.
East facing is best. That way the morning sun is warming up the bat house as the bats have just returned from being out all night. Southeast and south facing are the next best options.
This mostly matters if the bat house is on a building. If the bat house is on a post, then the orientation isn’t as important since the back half of the bat house isn’t being blocked from the sun by a building.
I have a question. Does it matter which side of structure you mount the bat box? Like do you want to mount it facing east so it doesn’t get too much late afternoon sun to heat up the box or the opposite do you want it to be in the sun at the end of the day so it will hold it for them overnight? Does it even matter? What if it’s in the shade all day? Thank you very much for what you guys do.