Blue Ridge Naturalist: Eastern Red Bat


© Marlene A. Condon

This female Eastern Red Bat was clinging to the wall right outside the entrance to a grocery store in Crozet. You never know where you’ll spot wildlife so keep your eyes open, no matter where you are! (Photo: Marlene A. Condon)

The Eastern Red Bat (Lasiurus borealis) is perhaps the easiest of the 16 recorded species of bats in Virginia for people to get to see well. This beautifully colored flying mammal often migrates in fall during daylight hours when its red coloring is quite noticeable. Male red bats have bright orangey-red fur while females sport a dull brick-red or chestnut pelage (the technical term for a mammal’s fur coat).

Watch for red bats flying near woods and water as these animals move from northern states to southern ones. Historical accounts from the late 1800s tell of large migratory flocks of red bats flying during the day along the Atlantic seaboard, using the same routes as migratory birds. Sadly, there were no such reports during the 20th century, indicating a decline in their populations.

In Virginia, it’s not uncommon to see one or more red bats flying as late as December, usually on sunny days with temperatures in the 50s when there can be midge and stonefly hatches.

Midges are tiny insects related to mosquitoes, but only some species bite. The larva, or immature form, develops in water. When the adult stage is reached, the midges emerge in large numbers that can be seen as clouds of insects in the vicinity of streams. Stoneflies also spend the immature stage of their lives in water, emerging as adults in large numbers. Red bats can easily feed on these hatches by flying through them and catching the little critters directly in their open mouths.

If you are lucky enough to see red bats feeding, you will have the opportunity to watch them for several minutes as they swoop around in a limited area, providing you with great views. I’ve watched Eastern Red Bats feeding over my yard. I’ve also seen them flying in Douthat State Park in Bath County as I was birding.

On December 19, 2002, my husband reported seeing two of these animals flying along route 664 near Sherando Lake in Augusta County. This road runs by a stream so there could have been a hatch to feed the bats as they flew at, or just below, tree level.

This female Eastern Red Bat was clinging to the wall right outside the entrance to a grocery store in Crozet. (Photo: Marlene A. Condon)

The red bat feeds exclusively upon insects. Moths, beetles, plant and leaf hoppers comprise much of its diet in summer. In colder weather, flies and moths are its main sources of food because these particular insects are more active in cooler temperatures than most kinds of arthropods (invertebrate animals with jointed legs, a segmented body, and an external skeleton, known as an exoskeleton).

Stomach biopsies have shown that the red bat doesn’t just feed upon flying insects.  It may glean cicadas from leaves as well as take crickets and grasshoppers from the ground.

It’s not unusual for red bats to rest on buildings during migration.  If you notice one resting, keep your distance so you won’t scare it. You can get a good look by using binoculars.

And, of course, never handle a bat. Although the incidence of rabies is low in our wild animals (otherwise it would wipe them all out, as it is a deadly disease), you should never chance getting bitten by trying to pick up an animal with your bare hands.  Remember this general rule of thumb for all wild animals, and you are highly unlikely to ever be bitten by one unless you sit or roll over or step on one or otherwise somehow threaten the animal’s well-being.

Although Eastern Red Bats inhabit Virginia, I’ve only ever seen these bats during their migration. One spring day in May I spotted one clinging upside down under the overhang of my carport. I feel confident this animal was on its way north because otherwise these bats typically hang by one foot in trees. They are thought to resemble dead leaves, a form of camouflage which protects them from predators.

The environmental role of the Eastern Red Bat is to help prevent overpopulations of a variety of insects so the environment can function properly. The bat is itself a food source for such animals as hawks, owls, and opossums.

You can help all of our species of bats by allowing caterpillars to survive on your plants during the growing season. Those caterpillars that transform into moths become a prime food source for these flying mammals. (And caterpillars of all types provide a critically important food source for adult birds to feed their nestlings.)

You needn’t worry about caterpillars seriously harming your plants if you create a nature-friendly garden that supports numerous kinds of predators. Predators keep caterpillar numbers limited to a level that will only impact your plants aesthetically—and only for a few weeks at that. Both herbaceous and woody plants will re-grow leaves, unless it’s late in the season when it’s time for plants to go dormant.