THE CASE FOR BATS by Cheryl Corson, RLA, ASLA
potential Zika virus host, the mosquito Aedes aegypti, has over-wintered on Capitol Hill since 2011. In a wonderfully ironic instance of having your mistakes come back to bite you, the Hill is home to some of the same members of Congress who left for summer recess without appropriating additional Zika research funds. Though the virus has not appeared in the Hill mosquitoes, entomologists note that this is the only known instance of the insects over-wintering north of Alabama (www.washingtonian.com/2016/02/26/zika-virus-mosquitoes-capitol-hillaedes-aegypti/).
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Zika or not, low-lying Capitol Hill has what mosquitoes Bat Basics like: access to water via the Anacostia River, plus small pools of Bats are small mammals that nurse their young just like standing water (maybe in your own backyard?) in plant saucers, other mammals. They are nocturnal and are most easmoist outdoor basement stairwells, or puddles made ily seen at dusk. Bats native to our area are very small, by leaky hoses. It also has weighing about the same as a nickmoisture in the underel. They hibernate in caves or abanground Metro, plus doned mines, and in our area mithe heated tunnels One important bat trait is grate south in winter, just like many around the Capibirds. Though they have very good tol complex. I’ve that they eat mosquitoes vision, they use their superpower of written about echolocation to locate prey in the this microcli– lots of them. dark. It is said that they can navimate before with respect to gate around something as fine as a roses, which thrive on the Hill. This is human hair. For more on echoloanother, though less desirable, examcation see http://animals.howstuffple. What to do? works.com/mammals/bat2.htm. One important bat trait is that they eat mosquitoes – Don’t Shoot! lots of them. Reports vary, but most say that a single bat can If you spray insecticide to kill mosquitoes, you are effectively eat 600 mosquitoes in one hour alone. That is why some killing other beneficial pollinators like caterpillars which belocal governments are encouraging them as nontoxic, polcome butterflies or, if eaten before then, food for songbirds, linator-friendly, bug-eating machines. who would also be poisoned. Working up the food chain, Do they have rabies? Will they fly into your hair and spraying for mosquitoes directly impacts the food web of the bite? Sources say that one-half of one percent of all bats Anacostia River and unavoidably the Chesapeake Bay. have rabies. This is less than other mammals. Vampire bats There are other pollinators that could be harmed by live in Central and South America, not here. Yes, if you see mosquito spraying that would like nothing better than to eat a bat in daylight, do not approach it, and keep your cat and mosquitoes every night by the hundreds: bats. Lately, towns like West Hempstead, Long Island, have formally endorsed these much maligned flying mammals by installing bat houses in public parks and gardens. With the northward creep of tropical diseases like Zika, dengue, and West Nile, bats are increasingly seen as part of the mosquito solution. While for some they lack the allure of a tiger swallowtail butterfly, for others they are as cute as hamsters. In favor of bats, not bombs, lifelong bat advocate Merlin D. Tuttle writes, “Chemical poisons kill natural mosquito predators more effectively than mosquitoes. Over time, predators such as fish, insects, and bats die out while mosquitoes develop resistance, multiplying in ever larger numbers in a losing battle often referred to as ‘the pesticide treadmill.’” (www.batcon.org/pdfs/bathouses/mosquitocontrol.pdf ) Before signing an insecticide application contract, consider the gentler alternative – inviting bats into your yard and your life. It’s not a panacea, but as we’ve already seen, Locally purchased bat house newly installed in Capitol Hill neither is spraying. alley. photo: Cheryl Corson.