They’re Back — or they never left?

One reason I haven’t posted as often as I would like here is that I was feeling a bit depressed since it seemed that all or almost all the bats had rather suddenly left the bat house in July. The number of bat transitions — bats passing in or out of the bat house opening — had plummeted.

In June, I logged an average of 64 transitions per night, with at least a few detected every night. But in July, the number dropped to 38, and there were long runs of zero or very few ins and outs. Strange. By early this month, things were very quiet around the backyard.
The amount of bat guano collecting on a board positioned below the bat house also dropped, and I no longer heard lots of shrieks and screeches every time I walked under the house. I began to consider why the bat house might become unattractive to bats. True, it is getting old, having been up some seven years and several hurricanes. I hypothesized that perhaps leaks had formed in between the boards, aggravated by the especially rainy summer we’re having. I had caulked the seams last summer, but maybe the house needed another going over. I was smelling the distinctive odor of free-tailed bats less as well. Something seemed to have changed.

I actually stopped logging nightly bat transitions for a while, since nothing seemed to happen on the counter.

But tonight I turned on the audio feed from the bat detector, and just at dark, I was surprised to hear a burst of bat echolocation calls. I sprinted out of my workshop and sat down in a lawn chair near the bat house to watch. Over the next twenty minutes, I counted 17 bats emerging. Now it may just be my excitement from seeing that not all the bats had left, but it seemed to me that these bats were a bit larger than the ones I usually saw emerging. Maybe another species had moved in?

Maybe I’ll poke the video camera back inside the bat house soon and just take a look around. Meanwhile, welcome back.

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