Bats: The Unseen Ally
By Jo Ann Abell | Apr 2, 2019
Photo by Getty Images/Mumemories.
Few animals in history have been so misunderstood and maligned as bats. For centuries, these flying mammals have been associated with evil and death, and reviled as carriers of disease. The media has perpetuated these myths, portraying them as frightening, bloodsucking, rabies-infested flying vermin, giving a bad rap to creatures that really do a lot of good. However, in the last couple of decades, thanks to the efforts of conservation groups and federal and state wildlife agencies, bats are being seen in a different light for the valuable role they play in our ecosystems.
North America is home to 47 species of bats. Most are insect-eaters, the exception being three species that feed on nectar and pollen and are found throughout the southwestern United States and Mexico. Texas holds the title of “battiest” state in the country — 32 bat species call the Lone Star State home at various times of the year. According to Bat Conservation International, bats make up about a fifth of the world’s mammal population.
An adult bat clings to a tiny slice of watermelon. Photo by Getty Images/JohnMaldoror.
Bats are nocturnal, hunting in the dim hours between sunset and sunrise. Contrary to popular perception, they aren’t blind. They can see, though many species use echolocation, navigating the night sky by emitting high-pitched (ultrasonic) noises and listening for the echoes to return. The sound waves reflect off objects, such as insects and surrounding obstacles, allowing bats to process the received data into a navigational layout in dark surroundings.
As the primary predators of night-flying insects, bats are critical to reducing insect pest populations, including those pesky mosquitoes that take some of the fun out of summertime and carry diseases. Bats are part of a healthy ecosystem, and integral to the balance of nature.
If mistakenly caught in your home, bats will often land somewhere they can hang, such as on curtains. Photo by Getty Images/fermate.
Brown and Red Bats
One of the most common native North American bats, the big brown bat is widely distributed throughout the contiguous United States. Russet to dark brown in color, this bat averages 4 to 5 inches in length with a wingspan of about 13 inches. Its favorite roosts include attics, barns, bell towers, window shutters, and man-made bat houses. These efficient feeders prey on a wide variety of nocturnal insects, including beetles, flies, June bugs, moths, and mosquitoes.
The big brown bat is one of the most common bats of North America. Photo by Getty Images/Ivan Kuzman.
Little brown bats look a lot like big browns, but are smaller, averaging 3 to 3-1/2 inches in length. Found throughout most of the country, they can be identified on the wing by their swift, erratic flight. They voraciously consume thousands of insects in one outing, eating as many as 1,000 insects in an hour! Mated females form maternity colonies inside abandoned buildings, hollow trees, rock crevices, or similar areas. Males and unmated females roost under shingles, the eaves of buildings, loose tree bark, and in rock outcroppings.
Bats sometimes form colonies inside abandoned buildings, hollow trees, rock crevices, or similar areas. Photo by Adobe Stock/katpaws.
Every May, a small number of little brown bats take up residence in our porch eaves. We haven’t mowed the fields for the last few years in an effort to create a diversity of trees, plants, and wildflowers that provide food, habitat, and cover for all wildlife, including insects. Our neighbor’s pond helps lure in the bats by attracting many of the water-breeding insects on their menu. We embrace these insect-eating machines that dine on beetles, mosquitoes, moths, stink bugs, and a host of other insect pests. In fall, when the nights start getting colder and insects are hard to find, our furry friends fly off to their winter hibernation site to wait for spring.
One of North America’s most colorful bats, the eastern red bat ranges in color from rusty-red to yellow-brown. Short, rounded ears and swift flight at low levels mark this bat as it forages for beetles, cicadas, crickets, moths, flies, and other insects. Red bats are found in wooded areas east of the Rocky Mountains from Canada to as far south as central Florida, roosting in trees, where they resemble dead leaves or pine cones.
Free-Tailed and Long-Nosed Bats
The Mexican free-tailed bat is found throughout most of the southern half of the United States. Its colonies are the largest congregations of mammals in the world. Besides caves, free-tailed bats roost in culverts, old buildings, tunnels, and under bridges. These bats get their name from the fact that their tail is almost half their total body length, extending beyond the membrane that stretches between their hind legs and tail.
There are hundreds of free-tailed bat species around the world, including the Kenyan big-eared free-tailed bat. Its North American cousin, the Mexican free-tailed bat, forms the largest congregation of bat colonies in the world. Photo by Getty Images/Ivan Kuzmin.
When hungry free-tails come out at sundown, humans reap the benefit. In central Texas, for example, every night about 15 million free-tailed bats emerge from Bracken Cave to cruise over lawns, gardens, farm fields, and orchards, gobbling up insect pests. According to Fran Hutchins, director of the Bracken Cave Preserve, “As the bats munch their way through nearly 300,000 pounds of bugs each and every night during the growing season, they provide a huge, mostly hidden, service to U.S. agricultural communities.” And that’s not all. A study in Uvalde, Texas, revealed that free-tailed bats ate 44 different agricultural pests, 20 of which are migratory, meaning that the bats are intercepting vast pest migrations and helping to lessen their spread.
Mexican long-nosed and lesser long-nosed bats are keystone species in the ecosystem of the Sonoran Desert in the southwestern United States. The bats’ head shape and long tongue allow them to delve into flower blossoms and extract both pollen and nectar. As they travel from flower to flower, they transfer pollen dusted on their bodies, which causes the plants to produce fruit. Worldwide, more than 500 species of plants rely on bats for pollination, many of which we use for food and medicine. Bees, moths, lizards, birds, and other wildlife depend on plants pollinated by long-nosed bats, either for food or shelter. Indeed, if the bats were to disappear, there would be serious disruption to the world’s ecosystems.
Illustration by Brad Anderson.
- Bats lose suitable habitat every year as land is gobbled up by homes and industrial development. You can help provide these useful creatures with places to live and feed by making a few adaptations to your landscape.
- Bats will live in man-made bat houses if they’re placed on a south-facing structure away from natural predators. (Don’t mount them on trees; bats will be more vulnerable to predators, plus their branches obstruct sunlight and make it difficult for the bats to drop into flight.) Bat houses and kits can be purchased online, or you can make your own with plans from Bat Conservation International, a nonprofit organization working to conserve the world’s bats and their habitats. Search “bat house plans” on the Bat Conservation International website to find plans and tips for building your own bat house.
- Bats prefer habitat with different types of cover, such as a mix of open and wooded areas. Plant a variety of perennials, herbs, and night-blooming flowers, such as moonflower, evening primrose, cleome, and nicotiana, to lure nocturnal insects; and avoid using pesticides.
- Bats are drawn to aquatic areas, where insect populations tend to be greater. Adding a pond or wetland to your landscape will help ensure lucrative foraging for bats.
All bats struggle to adjust to environmental changes. Most produce only one offspring per breeding season, and often live in large colonies that can easily be wiped out in a single catastrophe. These traits leave bats extremely vulnerable to extinction. With many species suffering population decline due to loss of roosting habitat, loss of wetlands (which serve as insect breeding grounds), and pesticide poisoning, people can do their part to help stem the tide by making their home landscape more bat-friendly.
Hang bat houses away from predators, never on trees. Photo by Adobe Stock/canduscamera.
Welcoming bats will pay dividends in terms of organic pest control. These winged wonders have long played an important role in nature’s systems of checks and balances. In a healthy, diverse ecosystem, for every insect pest we might find, there’s a natural predator. One of these is the silent hunter of the night — the underappreciated bat.
Jo Ann Abell lives on a small farm in southwestern Virginia with her husband, three dogs, chickens, and 200,000 honeybees.
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