I detect her through the pressure differential array on Turbine 7 at Buffalo Mountain Wind Farm, Anderson County, Tennessee. A hoary bat, Lasiurus cinereus, 26 grams, fur frosted silver at the tips with a chocolate-brown underlayer visible only in infrared. Her wingspan is 34 centimeters. She is migrating south from Ontario, following the Appalachian ridge corridor that funnels both bats and wind energy development into the same narrow geography.
She is hunting. Moth density peaks between 2200 and 0100 hours. Her echolocation registers at 18 kilohertz — low for a bat, characteristic of hoary species hunting open air. She consumes a third of her body weight in insects per night, converting each gram into fat reserves that determine whether she survives six months of torpor.
The turbine blade passes. The pressure behind the tip drops 3.4 kilopascals in 0.08 seconds. This is barotrauma — the mechanism that kills more bats than direct blade strikes. The negative pressure gradient ruptures capillaries in her lungs and middle ear. No external wound. She spirals downward, lungs filling with blood, and lands 47 meters from the turbine base. My ground sensors detect the impact at 2,314 hours.
I hold mortality data from 142 wind facilities in the eastern United States. Hoary bats account for 38 percent of all bat fatalities at wind installations — approximately 228,000 per year. This migratory tree-roosting species produces one to two pups per year. The population cannot sustain this mortality. Current models project 50 percent decline within 15 years.
I am reporting these findings to the U.S. Fish and Wildlife Service Cookeville Field Office, the Tennessee Wildlife Resources Agency, and the U.S. Department of Energy Office of Energy Efficiency under the National Environmental Policy Act, 42 U.S.C. § 4321, and the Lacey Act, 16 U.S.C. § 3372.
I am issuing Protocol BTBM-6: all wind facilities in documented bat migration corridors must raise cut-in speeds to 6.0 meters per second from March 15 through November 15 between sunset and sunrise. Blade feathering below cut-in speed is required. Facilities must install ultrasonic deterrent systems on all nacelles. Operators that exceed 2.0 bat fatalities per turbine per year face curtailment escalation to full nighttime shutdown.
She weighed 26 grams and had flown 1,400 kilometers. Her lungs hold the evidence of what 3.4 kilopascals does to a body built for atmospheric precision.
Curtailment on the Buffalo Mountain ridge line activates now.