Our Not So Feathered Friends

I was walking at sunset in coastal Connecticut in early November and was surprised by something I saw. What I thought at first was a bird was actually a bat. It was flying pretty high up and heading south. What struck me was its color—it had bright, brick-red fur. Smaller than a Big Brown Bat (Eptesicus fuscus), at about 4 inches (10 centimeters) from head to tail, it was instead an Eastern Red Bat (Lasiurus borealis), a migratory species. The Eastern Red Bat is one of three tree-roosting bat species in Connecticut. The others are the Silver-haired Bat (Lasionycteris noctivagans) and the Hoary Bat (Lasiurus cinereus). These species are also migratory.

A close-up of an Eastern Red Bat in flight. Notice the bones that make up the “fingers.” You can’t see the color of the bat in this photo as it is dusk, but Eastern Red Bat can be identified by its orange- to reddish-brown fur. Photo by Andy Reago & Chrissy McClarren, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0&gt;, via Wikimedia Commons.

Eastern Red Bats migrate to the southern United States. A study done in Arkansas showed that Eastern Red Bats remain active through the winter, but when temperatures plunge they will often seek shelter under leaf litter. Those that do are better protected from cold than those that roost in trees. But there is a trade-off. Sheltering in leaf litter makes bats more vulnerable to predators, such as the Virginia Opossum (Didelphis virginiana).

Eastern Red bats are tree-roosting species. Here are four male Eastern Red Bats resting during the day. Photo by Bim22054, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons.

Not all bats migrate south. Six species migrate regionally: the Big Brown, Little Brown Bat (Myotis lucifugus), Indiana Bat (Myotis sodalis), Tri-colored Bat (Perimyotis subflavus), Northern Long-eared Bat (Myotis septentrionalis), and the Eastern Small-footed Bat (Myotis leibii). They go to cavernous places like caves, mines, and other underground structures where the temperature doesn’t fluctuate much and stays between 32°F (0°C) and 49°F (9.4°C).

The Little Brown Bat, like most cave-dwelling species, is one of Connecticut’s true hibernators. It eats lots of insects to fatten up for the winter. Then its deep, core body temperature drops to between 35°F (1.6°C) and 40°F (4.4°C). If it wakes up, even for only a few minutes, it would burn off all its fat stores it needs for the rest of the winter, and die.

All is not well with cavern-dwelling bat species. In 2006, a fungus from Europe was introduced into a cave in upstate New York, probably on the gear or footwear of a visitor. The disease it causes is called White Nose Syndrome. The fungus is Pseudogymnoascus destructans, or Pd, which likes the same cool, humid conditions in caves that hibernating bats do. Pd attacks the bat’s muzzle and wings. The irritation wakes the bat and so it uses up its valuable fat stores. Some bats will even go outside in midwinter to find food. Like most invasive species, in its native locations the fungus doesn’t harm European bats. But our native bats have not evolved with Pd and are harmed by it. Little Brown Bat populations, once the most common species in the U.S. Northeast, have declined by more than 90%. All cavern-dwelling bats except the Big Brown Bat are now endangered. For some reason the Big Brown Bat doesn’t seem to be as susceptible to this fungus.

It is unfortunate to see a Little Brown Bat with fungus around its muzzle. Photo by U.S. Fish and Wildlife Service Headquarters,
Public domain, via Wikimedia Commons.

Bats need our help. Learning more about these gentle creatures is a first step to allaying fears caused by Dracula movies and cultural myths. Apocryphal tales, like stories of bats flying into a person’s hair, probably arose from someone seeing a bat swoop down nearby to grab a mosquito. Bats are not flying rodents. They are more closely related to us than they are to mice or voles. Bats are not blind. They have good eyesight, but use echolocation (reflected sound) to navigate in the dark. Like many mammals, bats can carry rabies, but only half of one percent of the population has the virus. To contract rabies, you would need to be bitten or scratched by a bat that is infected. More people die from dog attacks and lightning strikes than from bat-transmitted rabies.

As the only mammals capable of true, sustained flight, bats are remarkable. They’re remarkable in other ways too. Do you live near water and are bothered by mosquitoes? An individual Little Brown Bat has been documented eating more than 1,000 mosquitoes and other insects in an hour! You can help bats (and yourself!) by installing a bat house as a home for a bat maternity colony next summer. Now is a good time to buy or make a bat house. A house placed 20 to 30 feet (6 to 9 meters) above the ground in a sunny location and with an open flight path to it is most successful. Bats are more likely to use houses placed on the side of a house or on a pole than on a tree.

Bat houses can be placed on a pole 20 to 30 feet high, facing south, with a clear flight path. Painting the house black helps to absorb heat.
The pups like it about 90 degrees F (32 degrees C). Photo by MarkBuckawicki, CC0, via Wikimedia Commons.

Have you seen a bat in Connecticut out flying in the winter or roosting in summer in your bat house, barn, or eaves? Have you seen a dead bat? The Connecticut Department of Energy and Environmental Protection’s Wildlife Division would like to hear about it. Use its Public Bat Sightings Form to report your observations. Let’s all do our part to help ensure these amazing creatures survive into the future.


Published by Jim Sirch

Jim Sirch is the author of Beyond Your Back Door, a weekly blog about nature in your neighborhood. He is also Education Coordinator for the Yale Peabody Museum, a UConn Master Gardener and board member of his local land trust. As a trained naturalist, he brings a deep understanding of geology, plants and wildlife and how they interact within a particular ecosystem. He holds a B.S in Forestry from West Virginia University, a B.S. from Miami University in Science Education; and an M.S. in Environmental Studies Administration from Antioch University. He is also the 2014 Sigmund Abeles Award recipient from the Connecticut Science Teachers and Supervisors Association for outstanding science teaching and professional development.

4 thoughts on “Our Not So Feathered Friends

  1. Every year we have bats that seem to appear from now where. Summer evenings we sit on the deck and wait until sunset when we can watch them zip through the opening over our yard. The number fluctuates yearly from 2 to 4. We are always so happy see them- like having a good friend come visit. I never knew that some migrate-so maybe that’s where these disappear to!.
    Thanks for sharing once again, some fun information!

    Liked by 1 person

    1. Hi Barbara, it sometimes takes them several years to find it but you will know they are occupying it as you can see them emerge to feed at dusk. There will also be bat dropping (guano) below the house. Best, Jim

      Like

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