Bats of the Devils River State Natural Area- Big Satan Unit, Val Verde County, Texas




Allred, F. Grayson
Dowler, Robert C.
Ammerman, Loren K.

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A survey of bats is being conducted to determine the species diversity and community composition at Devils River State Natural Area (DRSNA) – Big Satan Unit, as part of ongoing research with the Texas Parks and Wildlife Department. The DRSNA is a 38,000-acre preserve situated along a 10.8-mile stretch of the Devils River in Val Verde County, 40 miles north of Del Rio, Texas. A handheld acoustic monitoring device, the Echo Meter EM3+ Ultrasonic Recorder, was used to detect species based on echolocation calls. Calls were recorded along an 8-mile long transect route that runs generally west to east across DRSNA, and at three stationary netting sites around the survey area. Echolocation calls vary among bats allowing species to be identified in flight. An analysis software system, called Kaleidoscope, was used to analyze the sound files recorded. Kaleidoscope is an integrated suite of bat data tools designed to help quickly convert files, and sort and categorize bat data by species. From a total of 3,845 sound files recorded so far, 699 have been recognized as good bat echolocation calls that can be used to identify species, while 3,146 were eliminated as noise files. Preliminary results found seven species (Lasiurus borealis, Lasiurus cinereus, Lasionycteris noctivagans, Nycticeius humeralis, Parastrellus hesperus, Perimyotis subflavus, Tadarida brasiliensis) present at DRSNA. We will continue to collect data for the next year and hope to predict bat species distributions, map centers of high diversity, and identify key conservation areas at Devils River.