Bats Mother Nature’s natural pest control

Published 1:00 am Saturday, March 17, 2012

Bats are important to the health of many ecosystems according to Chester Martin, artist, naturalist and certified wildlife biologist.

Martin calls them “winged wonders of the night,” noting they hunt and consume pesky insects, fertilize plants with their guano (excrement), pollinate plants and trees, help disperse seeds that contribute to forest renewal and serve in the food-chain for owls, raccoons and snakes.

Bats can be found everywhere on our planet except the most arid and polar regions. They comprise nearly one-fourth of all mammal species. In fact, there are nearly 1,000 species, most of them living in tropical areas where they are critical to the dispersal of seeds for food crops such as bananas, dates, figs and avocados. There are 45 species residing in the United States, 40 percent of which are threatened or endangered. In Mississippi there have been 15 species documented, two of which are on the U.S. Fish and Wildlife Service endangered list. The Big Brown Bat, Evening Bat and Eastern Red Bat are the most prevalent in our area.

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Bats pose very little threat to humans. Less than 0.5 percent carry rabies, but bats have been misunderstood, feared and persecuted by man for centuries due to misconceptions.

These shy, gentle creatures fill an important ecological niche. Bats in the U.S. feed almost exclusively on insects and can eat 50 percent or more of their body weight each night, which may be 3,000 or more insects according to Martin. Mosquitoes are often a large portion of their diet as well as leafhoppers, beetles, flies and moths which damage crops and ornamentals. They are not affected by the West Nile Virus and it is estimated that bats save farmers $3.7 billion a year on insect control.

In the 1980s, scientists around the world became alarmed about the decline in bat numbers and established Bat Conservation International. There are many reasons associated with their decline but much of it is associated with decreased habitat; human actions such as killing, vandalism and disturbing colonies; water quality; exposure to pesticides; and lack of conservation efforts.

Martin formed a Mississippi group, the MS Bat Working Group, affiliated with the Southeastern Bat Diversity Network, about 10 years ago. Its 100 or so members come mainly from Federal, State and University systems and the private sector. They study and work to address bat conservation, management and the coordination of research and management within our state.

White nose syndrome, a disease affecting bats in the Northeastern section of the United States, is one of the major issues endangering the U.S. bat population. The U.S. Fish and Wildlife Service announced in January that 5.7 million bats have died from this syndrome.

Martin says it has not been a big problem here yet because we don’t have the large caves they have in the northeastern areas where so many bats have contracted the disease. Many of our bats roost in trees, under loose bark and leaf litter.

Loss of habitat is a major issue, particularly the loss of so many old bottomland hardwoods. Some species found in Mississippi roost in old structures, bridges, cisterns and culverts, which have become important sites with the elimination of so many larger trees.

Bat houses can be erected in open areas near water, however, only two or three (including the Big Brown Bat and Evening Bat) of the 15 species found in Mississippi will use a bat house according to Martin. Bat houses should be attached to a sturdy, stable post at least 15 feet tall, in full sun and at least 20 to 30 feet out from a wooded area but within a mile of a still water source such as a livestock pond or lake. Water proximity is important because the nocturnal bats are generally dehydrated when they venture out each evening to seek food after roosting throughout the daylight hours.

They skim over the water, locate insect prey using echolocation and sight to feed, rest and then continue feeding until daybreak. Mothers with young will go back to feed the babies during the nighttime feeding hours.

Bats are nature’s natural pest control. The Mississippi Natural Museum of Science fact sheet states that a single brown bat can catch 1,200 mosquito-sized insects in just one hour and a colony of brown bats can protect local farmers from up to 33 million or more rootworms each summer. They also state that research has shown a correlation between an area with high bat species diversity and abundance to be a healthy, diverse forest.

Some bats may move into buildings or other places where humans do not want them. The best approach is prevention. Install one-way valves over openings through which a bat can enter a house or building or permanently close openings when bats are not present. This is usually September through March or at night after bats have left to feed Martin recommends. Young bats; however, should never be left trapped inside a building. For info and assistance with bat issues, email: msbats@hotmail.com.

Much of our county is forested with numerous small ponds, lakes and bats. Martin cautions to never pick up a bat and tell children never to do so. Not aggressive by nature, when startled or disturbed, they are unpredictable. Only an experienced biologist wearing gloves should handle them, particularly those which are injured or sick. Whenever possible, leave dead trees in woodland areas standing to provide safe roosting sites. Never shoot, poison or otherwise harm bats. Martin is a firm believer that education is key to protecting and conserving bat populations around the world.