Dogs Detect Larger Wind Energy Effects on Bats and Birds

Abstract

As wind turbine‐caused mortality of birds and bats increases with increasing wind energy capacity, accurate fatality estimates are needed to assess effects, identify collision factors, and formulate mitigation. Finding a larger proportion of collision victims reduces the magnitude of adjustment for the proportion not found, thus reducing opportunities for bias. We tested detection dogs in trials of bat and small‐bird carcasses placed randomly in routine fatality monitoring at the Buena Vista and Golden Hills Wind Energy projects, California, USA, 2017. Of trial carcasses placed and confirmed available before next‐day fatality searches, dogs detected 96% of bats and 90% of small birds, whereas humans at a neighboring wind project detected 6% of bats and 30% of small birds. At Golden Hills dogs found 71 bat fatalities in 55 searches compared to 1 bat found by humans in 69 searches within the same search plots over the same season. Dog detection rates of trial carcasses remained unchanged with distance from turbine, and dogs found more fatalities than did humans at greater distances from turbines. Patterns of fatalities found by dogs within search plots indicated 20% of birds and 4–14% of bats remained undetected outside search plots at Buena Vista and Golden Hills. Dogs also increased estimates of carcass persistence by finding detection trial carcasses that the trial administrator had erroneously concluded were removed. Compared to human searches, dog searches resulted in fatality estimates up to 6.4 and 2.7 times higher for bats and small birds, respectively, along with higher relative precision and >90% lower cost per fatality detection. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.

Relating Bat Passage Rates to Wind Turbine Fatalities

“…The dogs were tested on 95 bat carcasses that we placed in 132 detection trials during this study (some bats were redeployed in second trials). Our dogs achieved a detection rate of 95% [31].…”

“…Our dogs found fewer fresh fatalities than our observed collisions suggest they should have found, and yet our dogs performed near perfectly at finding bat carcasses in detection trials. The dogs even found all 34 baby bats placed in trials, and nearly all of the bats that had already decayed for days in the field before being redeployed in trials [31]. Nevertheless, despite their exemplary performance in detection trials, of the four bat collisions we witnessed at turbines to be searched the next morning, dogs found only one of them.…”

“…The dogs were tested on 95 bat carcasses that we placed in 132 detection trials during this study (some bats were redeployed in second trials). Our dogs achieved a detection rate of 95% [31]. Working with dogs, we searched for fatalities at the same turbines the following morning after each nocturnal thermal imaging survey.…”

“…To determine whether any chance exists for accurately predicting bat fatalities from pre-construction activity patterns, we first determined whether we could detect a relationship between bat activity and fatality finds among operational wind turbines. To do this, we maximized our detection of fatalities by using scent-detection dogs [29][30][31] and linked those fatalities to activity patterns observed only the night before each fatality search. We also worked harder at detecting fatalities before vertebrate scavengers had time to find and remove them [31,32].…”

“…To do this, we maximized our detection of fatalities by using scent-detection dogs [29][30][31] and linked those fatalities to activity patterns observed only the night before each fatality search. We also worked harder at detecting fatalities before vertebrate scavengers had time to find and remove them [31,32]. We maximized our observations of bat activity by using a thermal imaging camera to view all parts of the rotor-swept plane, including its outer edge where nacelle-mounted acoustic detectors would fail to detect bat passages [33].…”