“Why is my bat box empty?”
Bats are wild animals and, like all wildlife, cannot be totally controlled by humans or be forced to move into a bat house. There are many reasons why they may choose not to live in a bat box:
1 The bats in your area may be very happy in a nearby safe roost and decide not to leave their home unless they are excluded from the roof of a building, for example. 2 The bat house is being disturbed too much (shining a flashlight into the house every day or during the night to see if bats have moved in is not a great idea, for instance). The telltale sign of occupancy is a collection of guano on the ground below the box. 3 The bat house is not getting enough sunlight to warm up the box. Observe the position of the sun carefully, taking all four seasons into account, before installing the bat house. Ideally it should be in a position where it can absorb the northwesterly sun in the late afternoon. 4 The use of insecticides in the garden or on crops that are poisonous to mammals when taken orally may mean the bats have either died from eating insects contaminated by the chemicals, or they may have moved to safer grounds. 5 The food source for the bats has decreased. This may happen when insect populations decline during winter, which is natural, or when large stretches of grassland or bush have been cleared around the bat house. In both cases the bats will probably return when their food source returns. 6 Bats like warm, dry roosts and will go in search of such spots if their bat box is too cold and wet. This may happen if rainwater leaks in or the bat house is positioned incorrectly.