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The Case of the Missing Bat

NOTE: For photos, I suggest you visit the various blue links throughout this post.

Beyond the ghosts and goblins (and now zombies), Halloween is a time for bats. I’m not sure why this is so, but I can guess it’s because they are spooky, elusive, misunderstood creatures of the dark. Our rare encounters usually involve the big brown bat (Eptesicus fuscus). Because, it’s the least selective bat in my home state of Pennsylvania when it comes to habitat, it is often the lead character in the story that starts, “My wife screamed that there was a bat in the house.”

Yet, if you choose to go to a costume party dressed as a bat, you should do so with reverence. That’s because the big brown and, more particularly, its cousins in the Vesper bat (Vespertillionidae) family are experiencing a mass extinction for numerous reasons.

The most devastating is the deadly White-nose syndrome. For example, when all of Pennsylvania’s main hibernation sites became contaminated, 99 percent of the northern long-eared bat (Myotis septentrionalis) using those locations died. That’s just in Pennsylvania. As of 2016, the fungus had spread to 28 states and five Canadian Provinces. To give you a better sense of the impact, the Indiana bat (Myotis sodalis), for example, hibernates in clusters of about 250 bats per square foot. White nose has killed at least 6 million bats in the Northeast and Canada.

The fungus that causes it threatens hibernating bat species, of which there are six in Pennsylvania. For those that migrate (of which there are three), wind turbines are the enemy. Fortunately, responsible turbine manufacturers and operators have worked closely with scientists to reduce the mortality rate by 44 to 93%, just by implementing a few design and operation techniques.

Regardless, we need bats. All of Pennsylvania’s bats feed exclusively on nocturnal insects. This includes the disease-associated mosquito and the tree-killing Hemlock Woolly Adelgid. One study estimated that their insect management work contributes $3.7 billion annually to the farming community.

Part of our problem with bats is that, like most nocturnal beings, we don’t know them. We can’t love what we don’t know, and we don’t protect what we don’t love. So here are few facts to help you get to know them better:

  • Bats are the only true flying mammal.
  • Bats are NOT rodents.
  • The Indiana bat is the only mammal in Pennsylvania that is on the Federal Endangered Species list.
  • Some wild bats have been known to live to age 25.
  • A bat’s body’s flight mechanism differs from that of a bird’s.
  • Bats typically weigh less than birds. The tri-colored bat (Perimyotis subflavus) weighs less than two pennies.
  • Mines and quarries have attributed to the existence of bats in Pennsylvania.
  • Bat boxes provide summertime habitat, but bats do not hibernate in them.
  • A bat sleeps through about 80% of its life.
  • A bat sleeps (hibernates) so deeply, its heart rate slows to one beat per minute.
  • It is believed that of the hibernating species, one bat consumes a million insects per year.

Researchers are greatly concerned, not just because of the implications of a sudden decline in bat existence, but because so few people are talking about them. Meanwhile, Jason Collins, a wildlife biologist with Normandeau Associates described this as, “the number one conservation emergency in the world.”

Foremost, humans must stay away from hibernating colonies. You and I must stay out of the caves. After that, ironically, one of the best things you can do to help the bats is to improve insect diversity. We need to improve their food supply. This means allowing space for tall grass in your yard. It means allowing water to pond in wooded places, which is the opposite of what the mosquito-control specialists advise. And it means avoiding fertilizers and pesticides in order to prevent the accumulation of toxins in their bodies (the implications of which are not yet fully known).

Bat presentation slide

Jason Collins’ bat decline presentation to the 2016 Watershed Congress Along the Schuylkill, available for viewing on YouTube.

You can also provide habitat by allowing dead trees to remain standing (some bats use them for roosting during the summer) or by installing bat boxes, high up, facing the sun. (email Jim Kerr of Feathered Friends Log Homes at for a price.)

If you want to donate to or get involved with the cause, Jason recommends Bat Conservation International or The Save Lucy Campaign.

Moreover, add this to the proof that protection of native species is our best hope for the protection of native ecosystems which have been protecting us all along. Learn about your native bats (Pennsylvania fact sheet). And this Halloween, take on your bat persona with honor.

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