Surveying White Memorial's Bat Population


 This summer, White Memorial adds its efforts to an ongoing survey of Connecticut's bat species. Begun in 2010 by the Department of Energy and Environmental Protection, the survey uses sound recordings to monitor bat activity. Starting a half-hour after sunset and continuing until late at night, White Memorial's research technicians drive a 24-mile route through the woods roads of the property, using a truck-mounted microphone to record high-pitched sounds. The microphone is sensitive to sounds well above the range of human hearing, and records the calls of bats as they seek out insects for food, along with any high-pitched background noise from nearby telephone wires, insects, and radio transmissions. We'll pass these recordings on to the DEEP, where computer analysis will distinguish the bat calls from surrounding noise and identify the bats by species based on their unique sound patterns. We'll likely find evidence of big brown bats (Eptesicus fuscus), little brown bats (Myotis lucifugus), and northern long-eared bats (Myotis septentrionalis), all known to inhabit White Memorial's property.

     Relying on acoustic recordings of bats allows us to form a much more detailed picture of bat populations, distributions, and activity than do older methods such as counting bats caught in mist nets. Furthermore, as white nose syndrome continues to decimate bat populations in the eastern United States, bat monitoring has become increasingly important. The white nose fungus (Pseudogymnoascus destructans) has been present in Connecticut since the winter of 2007-2008, when it was found among hibernating bats in northern Litchfield county. Bats affected by the fungus exhaust their fat reserves and die during their winter hibernation. Monitoring efforts at White Memorial and in towns around Connecticut will help measure surviving bat populations, determine which species are affected and not affected, and provide long-term data against which management efforts can be judged.

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