Saturday, July 04, 2009

A Place To Call Home

By Rosalie Rayburn
Copyright © 2009 Albuquerque Journal
Journal Staff Writer
          The Southern Sandoval County Arroyo Flood Control Authority has turned to an unusual source to protect the area's dams and ponds: bats.
        Why? Because bats have a taste for mosquitoes and other bugs that thrive near open water, especially during warm rainy weather.
        The flood control authority has a vested interest in reducing bug populations near water. The board-run authority was founded to protect Rio Rancho, Corrales and part of Bernalillo from flooding. It does so by building dams, ponds and structures that channel waters safely away from residential and business areas.
        A few years ago, authority staff began to receive calls from residents in the communities it protects concerned about mosquitoes.
        The insects, which breed near water, carry diseases like West Nile virus, a type of encephalitis that can be fatal to humans, horses and birds. Cases have occurred in New Mexico every year since 2003.
        Up until then, the authority had used chemicals to control mosquitoes, but Executive Director David Stoliker was worried about the harm they might do to frogs, fish and turtles which inhabit water bodies the authority oversees.
        "We didn't want to keep spraying pesticides," Stoliker said.
        The pesticides were only effective short term. After every rainstorm residents would call saying the mosquitoes had reappeared, he said.
        Through a news story in the Journal, Stoliker had heard about the Rio Grande Basin Bat Project, a Corrales-based nonprofit that promotes bat conservation and the use of bats as a biological alternative to pesticides.
        When reports of West Nile virus began to surface in New Mexico he thought the flying insect eaters might offer the authority an environmentally friendly solution to combat the bug problem.
        A Bat Project flier says just one of the palm-sized creatures, which weigh less than 15 grams — a paper clip weighs about one gram — can eat up to 4,500 insects in a single night.
        "If you compared that to a person, that would be like a 160-pound person eating eight 10-pound bags of potatoes — nightly," said Michelle McCaulley, president of the Rio Grande Basin Bat Project.
        McCaulley coordinates volunteers who erect and maintain bat houses. The authority is a sponsor, along with the U.S. Fish and Wildlife Service, the Corrales Harvest Festival and several local residents. Currently there are about 60 bat houses at locations throughout Corrales and Rio Rancho.
        The authority has erected one bat house off Meadowlark Lane near the back of Intel, two at the Harvey Jones outlet near Corrales Road and the Rio Grande, and one in the Corrales Heights neighborhood of Rio Rancho.
        The plywood houses measure roughly 3-feet by 18-inches and sit atop poles 14-feet to 18-feet high. Inside, a series of nylon screens provides a convenient spot for the bats to congregate. Up to 250 bats can cram into one house.
        "There's no personal space issues when it comes to living in a bat house," McCaulley said.
        Around two dozen bat species regularly stay in the mid-Rio Grande region. Mexican free tail, Yuma Myotis and big and little brown bats are some of the most common types, she said. They arrive in March or April and leave by October. During those months they typically leave the houses around dusk to spend a couple of hours foraging for food.
        Stoliker believes they're doing an effective job. The authority rarely gets calls about mosquitoes anymore.
        "Those doggone bats do a great job," he said.
        Despite Stoliker's enthusiasm, Paul Ettistad, state public health veterinarian at the New Mexico Department of Health, cautions that there is no hard evidence that an abundance of bats reduces the incidence of humans being bitten by mosquitoes.
        He recommends that bat houses be erected at least 100 feet away from residences. A small number, less than 1 percent, of bats in New Mexico, are infected with rabies, he said.
       

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