April 17 Flying Mouse Surprise

As I was riding to the Nature Center on Waunona Way, I noticed a bird in my right peripheral. I turned to give it a look and noticed a peculiar flight pattern with slow wing beats. It was no bird after all, but this bat! The little creature stopped on a utility pole and I stopped to walk back and inspect. It didn't like me approaching, even slowly, so it moved about 6 feet back to this position in a pine tree. From underneath, the bat didn't mind me taking photos, and I actually came back 5 hours later to get this one in more uniform light. I'm sending this photo to one of my bat friends, but for now my best educated guess is that it is of the big brown variety (Eptesicus fuscus). Big browns are only 4-5 inches long, which means little brown bats are tiny. Both are very common in Wisconsin and both spend the winter in hibernaculums, usually in caves. All seven species of bats in our state are insectivores, feasting on so many bugs each night it'll make your head spin. A single big brown bat will eat thousands of insects in one night. Insects include mosquitoes. Therefore, our bats serve an ecological function that goes almost entirely unnoticed, unless maybe we are camping or fishing at night and happen to see bats zipping low over the water or swirling through the trees. Sadly, the fungus that causes white nose syndrome, which kills over 95% of hibernating bats, has made it to Dane County. Millions of big brown, little brown, long-eared, and indiana bats will die in the coming years due to this fungus, which researchers believe arrived in New York from Europe in 2006. I watched this bat hang from one foot and sleep the afternoon away for awhile and felt so lucky to be seeing it outside, in my town! For me, the scariest thing about bats is what might happen to insect populations if so many of them die.