Among the chief rewards for wildlife gardeners is seeing the fruits of our labor: butterflies flocking around flowers in the morning or hummingbirds at the feeder in the afternoon.
For Cary’s Kathy Martin, that treat comes just before dark, when dozens of bats fly across her yard as they set out on their evening’s quest for flies, bugs, ants, beetles, wasps and similar dining options.
“I enjoy sitting on the patio in my side yard with a glass of wine and watching the bats come out,” Martin said. “My neighbors like to watch them the same as I do. Bats are such different creatures.”
The creatures in residence in Martin’s two bat houses are Mexican free-tail bats, Tadarida brasiliensis. These are brown or gray bats with short noses and bodies less than 4 inches long.
If you’ve ever visited Austin, Texas, you’ve probably seen or heard of this species; some 1.5 million of them live beneath the Congress Avenue Bridge. If you are a rum drinker, you might also recognize them from the Bacardi logo.
Martin said she became a fan of bats after seeing one inside her home about 10 years ago. She called a pest control company, and inspectors discovered that a small colony had set up a home in her attic.
People don’t want bats sharing their living quarters because of health hazards posed by guano, the bat droppings that make a fabulous fertilizer but may also develop illness-causing fungi if allowed to accumulate, said Lisa Gatens, curator of mammals at the N.C. Museum of Natural Sciences.
Long fascinated by birds and other backyard wildlife, Martin turned to Bat Conservation International, batcon.org, whose website is full of helpful tips on dealing with bats.
The site explains that there are 1,300 species, and all play an important role in pest control around the world. Many also pollinate plants and disperse seeds that are needed to repopulate our forests with the next generation of trees and plants.
A threat to bats
A major threat to North American bats is white-nose syndrome, a fungus that has spread from one New York cave in 2006 to 25 states today, including Western North Carolina, as well as parts of Canada, killing 5.7 million bats so far.
Other threats to bats come from deforestation and other habitat disruptions, including human intrusion into the caves and mines where many bats hibernate. The hibernation period is essential to the mammals’ ability to conserve energy in winter, when food sources are insufficient for activity.
Bats can be a great backyard resource, ridding the garden of harmful plant pests like beetles and worms, while also taking a bite out of the mosquito population. Some eat fruit or nectar. Others dine on small lizards, fish or smaller mammals. And, yes, in South America there actually are three species of vampire bats that feed on blood, but only one with a preference for mammal blood. They don’t suck blood but lap it.
The popular idea that most bats are rabid is overblown, Gatens said.
Bats behaving erratically, flying in populated areas during daylight hours, for example, are the ones most often tested for rabies, and fewer than 10 percent of those come back with positive results. Gatens’ advice is to treat bats as you would any other wild animal and do not touch or handle them.
Providing a habitat
But it’s not difficult – or dangerous – to provide a hospitable habitat.
Because Martin got the facts and didn’t react in fear after learning about the bats in her attic about a decade ago, she was able to oust them in a humane manner.
She discovered that most bats are born in May, which inspired her to delay eviction proceedings until fall, when the babies would be old enough to fly. And she spent the summer building a bat house based on plans from http://nando.com/16d.
In the fall, Martin fashioned a screen to block bats from entering her house. By leaving the screen unattached at the bottom and extending it several inches beneath the vent openings, bats were able to leave the attic but not re-enter – “basically creating a one-way door,” she said.
“Bats typically drop 10 feet when they leave their roost and start to fly,” she explained. “They have to gain enough lift, air under their wings, to fly. That’s what is happening a lot of times when people think bats are swooping at them.”
The bats who left her house that fall were heading southward for five months or so of hibernation. The next spring, they came back to her yard and adopted the newly crafted bat house as their new home.
Free fertilizer
Today, when she’s not bat watching on the patio, Martin works with parks and other organizations interested in building bat houses and advocates for support of the world’s only true flying mammals.
Ready-made bat houses, sometimes called bat shelters, are available online for $20 to $100, depending on size. Be sure to check the specifications to ensure your choice conforms to Bat Conservation standards. If you’re handy, use the organization’s plans to build it yourself for less.
Once the bats are relocated to the bat house, they take care of themselves. And as a bonus, you’ll get plenty of guano to fertilize the garden by simply shoveling up what drops to the ground beneath the house, Martin said.
For more information, including lists and descriptions of bats found in North Carolina, visit the Museum of Natural Sciences Web page at http://nando.com/16e.
Elder: wildlifechatter@gmail.com
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