Effects of Wind Turbine Curtailment on Bird and Bat Fatalities

Abstract

Bird and bat fatalities increase with wind energy expansion and the only effective fatalityreduction measure has been operational curtailment, which has been documented for bats but not for birds. We performed opportune before-after, control-impact (BACI) experiments of curtailment effects on bird and bat fatalities and nocturnal passage rates during fall migration at 2 wind projects, where 1 continued operating and the other shut down from peak migration to the study's end (study 1). We also performed BACI experiments during a 3-year study of curtailment and operational effects on bird fatalities among wind turbines of varying operational status (study 2). In study 1, wind turbine curtailment significantly reduced near-misses and rotor-disrupted flights of bats, and it significantly reduced fatalities of bats but not of birds. In study 2, converting wind turbines from inoperable to operable status did not significantly increase bird fatalities, and bird species of hole or sheltered-ledge nesters or roosters on human-made structures died in substantial numbers at vacant towers. Of bird species represented by fatalities in study 2, 79% were found at inoperable wind turbines. Because the migration season is relatively brief, seasonal curtailment would greatly reduce bat fatalities for a slight loss in annual energy generation, but it might not benefit many bird species.

Effecten van windturbines op vleermuizen in Vlaanderen: Testcase voor het risico op sterfte

“…Bovendien zorgt bijvoorbeeld het gebruik van getrainde honden voor een significant groter aantal gevonden slachtoffers dan bij een standaard zoekactie door mensen (Mathews et al, 2013;Rodrigues et al, 2014;Barrientos et al, 2018;EUROBATS, 2019). Bijvoorbeeld; in een windpark waar gerichte experimenten naar zoekefficiëntie werden uitgevoerd, vonden getrainde honden 96% van de vleermuizen, terwijl de standaard zoekpersonen slechts 6% van de vleermuizen vonden (Smallwood et al, 2020a). Daarom werd op het INBO ondertussen gestart met een testproject om in de toekomst getrainde honden in te zetten (Everaert, 2019).…”

Comprehensive Bird Preservation at Wind Farms

“…Rotating high speed wind turbine blades are hardly visible for hunting predatory birds. It is hard to estimate the accurate mortality rate, but the most recent studies show that in the U.S. between 140,000 and 500,000 birds die annually [9][10][11]. With the increase of wind energy capacity, this number could even reach 1.4 million.…”

Historical effective population size of North American hoary bat (Lasiurus cinereus) and challenges to estimating trends in contemporary effective breeding population size from archived samples

“…Infrared imaging has revealed a strong behavioral component of turbine strikes, in which individuals repeatedly approach wind turbine surfaces and moving blades (Horn, Arnett & Kunz, 2008;Cryan et al, 2014a). While fatality reduction strategies are being developed (e.g., Smallwood & Bell, 2020;Weaver et al, 2020), there is an urgent need to understand population trends concurrent with wind energy development, as our limited understanding can exclude neither extinction nor stable co-existence as eventual outcomes (Frick et al, 2017).…”