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Wednesday, April 18, 2012

White-nose syndrome is wiping out brown bats

Five years ago, a little brown bat got into our house. The kids found it clinging to the top of a doorway in the downstairs hallway. It was exciting; we had never seen a wild bat up close. As the responsible adult, I was elected to remove it. I approached with a jar — the idea being to trap it in the jar and release it outside. As I closed in, it looked right at me, bared its teeth and hissed. This was thrilling — what a ferocious little animal! I persevered and eventually returned it to the woods.

That was five years ago; little brown bats were common. All summer, they would flit back and forth over our driveway and fields, hunting insects all evening.

Just five years ago, in 2007, a disease called white-nose syndrome was discovered in a population of bats in upstate New York. Since then, it has spread throughout the Northeast and Canada. This winter, it jumped the Mississippi and was found in bats in Missouri, according to the Missouri Department of Conservation. Scientists were hoping it wouldn't spread into the south (The fungus was believed to thrive only in cool, damp conditions.), but this year it was found in Alabama after a particularly warm winter. The known death toll exceeds 5.5 million, with 100 percent mortality in many of the infected caves.

White-nose syndrome is caused by a fungus (Geomyces destructans) that often covers the bats' noses and wings with a powdery white growth and eats away at the membranes of the nose, ears and wings. Bats infected with white-nose syndrome behave erratically, often flying out of caves in the winter, using up the fat reserves necessary for successful overwintering. It isn't yet clear how this disease is spread or even how it kills the bats; scientists are currently investigating the fungus and searching for ways to control it. They'll hopefully figure out something soon.

Over 30 years ago, I had my most wonderful encounter with little brown bats. I was spelunking in the Shawangunks in New York in a cave in which ice stalactites and stalagmites sparkled in our miners' lamps. When our lights fell upon a little side cave, hundreds of hibernating bats shifted and shook off a casing of ice that fell to the ground, tinkling like breaking glass. Hundreds of eyes opened and reflected our lights. (In hindsight, we shouldn't have been in that cave; disturbing any wild animal in the winter is bad; they need all their energy just to survive.)

Scientists are fairly certain that white-nose syndrome is primarily transmitted from bat to bat, but there is also a strong possibility that humans can carry the fungus from cave to cave. As a result, many caves are now closed when bats are in residence.

According to the U.S. Fish and Wildlife Service, members of a number of different species have died from white-nose syndrome, but little brown bats seem to be the hardest hit at this point in time. This is one of the largest population declines from disease ever recorded for a mammalian species.

The night sky seems empty without them.

Source: Seacoastonline