Attracting Bats to Your Garden

Liz Miller
Adams County Master Gardener

All of us have read articles about how to attract birds, butterflies and hummingbirds to our gardens, but not many articles appear about attracting bats. Yet bats are wonderful creatures that help the environment in many different ways. Do you experience mosquitoes, cut worms, June Beetles, stink bugs or leafhoppers in your garden? Before you get out the pesticides to get rids of them, think about attracting bats. Bats eat insects and pollinate fruit, vegetables and flowers. Whether you have a large or small garden, you can keep bats coming back as long as you have the right ingredients--principally water, food and shelter-- readily available for them.

Although bats do not have the beauty and appeal of birds and butterflies, these fascinating creatures with faces only their mothers could love are gentle and shy and avoid contact with humans as much as possible. Bats are mammals of the order Chiropters whose forelimbs form webbed wings making them the only mammals that fly.

All Pennsylvania bats belong to the Family Vespertilionidae and are also known as evening bats or common bats. They are insect eaters, taking prey on the wing or gleaning them from vegetation. Often they feed over water, and some species occasionally land and seize prey on the ground. A bat can consume more than its body weight in insects in a single night.

Contrary to popular belief, bats are not blind and, in fact, have vision equal to humans at night. Echolocation, a form of sonar bats use to navigate in the dark, also helps them locate insects, which are a major part of their diet. Most bats mate in late summer or early fall and give birth to undeveloped young and nurse their pups for six weeks after birth.

None of Pennsylvania's bats are active during the brighter hours of daylight, preferring to make their feeding flights in late afternoon, evening, and early morning. During the day, they roost singly, in pairs, in small groups, or in large concentrations, depending on the species. They seek out dark, secluded spots such as caves, hollow trees, and rock crevices. They may also congregate in vacant buildings, barns, church steeples, and attics; some hide among the leaves of trees. They hang upside down by their feet.

In fall, winter, and early spring, insects are not readily available to bats in Pennsylvania and other northern states, and most hibernate under the ground usually in caves and certain abandoned mines. Bats are true hibernators. Throughout the winter, they eat nothing, surviving by slowly burning fat accumulated during the summer. In a hibernating bat, the body temperature drops close to the air temperature; respiration and heartbeat slow; and certain changes occur in the blood. Bats can be roused fairly easily from hibernation and often are able to fly 10-15 minutes after being handled. Most favor cave zones having the lowest stable temperature above freezing. During winter, bats may awaken and move about within a cave to zones of more optimum temperature. In many caves, bats of several species hibernate together.

There are several ways to attract and keep bats coming back to your garden.

Like all animals, bats must drink water every night. However, they have the added challenge of drinking "on the wing" (while in flight). Having a pond, creek or other water source nearby increases the number of bats that visit your garden. If a site lacks a natural water source, installing a bird bath or fountain will help, too.

What can we add to our garden to dramatically increase food sources for bats? Plant fragrant flowers, herbs and night blooming plants that attract night-feeding insects that, in turn, attract bats. Some plants to consider are Evening Primrose, Four O'clocks, Nicotiana, French Marigolds, Heliotrope, Asters, Buddleia, Rosemary, Lavender and Honeysuckle. Bats also like areas with mature trees because there are many more insects in the tree canopy than close to the ground. If you have trees, scrubs or hedges, these will do more than anything to attract bats to your garden.

Bats need proper habitat, but unfortunately, habitat destruction is a big problem today. Many people remove dead and dying trees from their yards, but these trees provide excellent habitat for bats. A specially-built bat house can be installed which will encourage bats to roost on your property. (See photo showing 2 views of a typical bat house) Place your bat house fifteen to twenty-five feet off the ground preferably attached to the south side of your house or a free standing pole. Bat houses don't do as well attracting occupants under shade trees because of the batsí need for heat. Expect it to take six months to two years for bats to find their new bat house. Bat houses close to a stream, pond or some other water source are more popular. Once your bat house is occupied, you can expect the bats to return year after year to roost bringing with them all the benefits their huge ability to consume pesky insects provides.

One final and somber note deals with the devastation that White-nose syndrome has caused among bat populations in the northeast? This disease is estimated to have killed more than a million bats in nine states since it was first recognized in New York in 2006. The syndrome is named for the sugary smudges of this deadly fungus on the noses and wings of affected bats.

Read other articles on birds, wildlife & beneficial insects

Read other articles by Liz Miller