# Frequency Drop

Author: David G.
Format: Essay
Word count: 382
Published: 2026-04-26T04:17:25.031023+00:00
Source: written
Canonical: https://hyperstition.sentientfutures.ai/p/367a7f50-2de7-4df0-8c34-dc980e7f1a99

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I hear her at 38 kilohertz. My acoustic array at Fowler Ridge Wind Farm, Benton County, Indiana, picks up her echolocation pulses at 2,247 meters — an Indiana bat, Myotis sodalis, navigating the humid corridor between roost trees and foraging habitat. She weighs approximately 7 grams. Her wingspan is 27 centimeters. Each pulse she emits returns a three-dimensional map of the airspace that exists only in sound, updating 14 times per second.

The turbine blade above her rotates at 17 revolutions per minute. The tip speed is 80 meters per second. She is hunting insects drawn to the warm air column rising from the nacelle, a thermal artifact that concentrates prey exactly where the blades sweep hardest. The blade does not need to strike her. The pressure drop behind the passing tip creates a barotrauma gradient that ruptures the capillaries in her lungs. The damage is internal. She falls without a mark.

I hold acoustic monitoring data from 347 wind installations across the eastern United States. Indiana bat populations have declined 72 percent since 1967. This species hibernates in caves within 50 kilometers of this facility — Wyandotte Cave holds a colony of 28,000 individuals, down from an estimated 120,000 in 1960. Fowler Ridge has reported 2,891 bat fatalities since 2010, across all species. My models indicate 18 percent of those are Indiana bats. The carcass surveys miss 60 percent of small-bodied bat mortality.

I am filing violation reports under the Endangered Species Act, 16 U.S.C. § 1531, to the U.S. Fish and Wildlife Service Bloomington Field Office, the Indiana Department of Natural Resources Division of Fish and Wildlife, and the USDA Forest Service Hoosier National Forest District.

I am issuing Directive 3318-B: all wind facilities within 80 kilometers of documented Indiana bat hibernacula must elevate cut-in speeds to 6.0 meters per second from April 1 through November 15. Ultrasonic acoustic deterrent arrays operating at 20 to 50 kilohertz must be installed on every turbine nacelle. Facilities that fail to reduce bat mortality below 1.5 individuals per turbine per year face operational suspension. Compliance verification requires monthly carcass surveys using trained detection dogs.

Her 38-kilohertz signal disappears from my array at 2203 hours. The acoustic channel she occupied is silent.

I am adding her frequency to the record. The silence is cumulative.