Back-to-back may be solution for big browns

Managing summer habitat for big brown bats has been partially successful in Pennsylvania. The roosting requirements for these creatures have not been thoroughly studied and are not completely understood. The following observations have been made over the past few seasons:

• Big browns have been found to occupy north facing (shady) bat boxes.
• They occupy some properly placed bat boxes only in the Spring and Fall.
• At certain properly placed boxes, big browns leave the box in late Spring suddenly only to be soon replaced with little browns.
• They tend to occupy barns rather than warmer attics throughout the summer.

Our observations suggest that a properly placed box for little browns may become too hot for the big browns.

This Spring we installed several Seven-Chamber boxes on posts in good habitat facing the standard 135°. On the backside of these posts we installed smaller Three-Chamber boxes. We hope the smaller box will provide an successful roost for big brown bats using an installation procedure which can be duplicated throughout northern North America.

Solutions for medium-sized evictions

For projects not large enough to require a large community scale condo solution, the alternative is simply several boxes. At this site a new roof was installed on a church which would have forced over 600 little browns to use their alternate roosts, which may well be neighbor's barns and attics in the community. To head off this problem three seven chamber bat boxes were installed this Spring near the church. These boxes have the capacity to hold this number of bats with some room to spare. Next year an additional box may be added to the backside of this structure for temperature, big brown, and overflow experiments.