USA Wind Energy-Caused Bat Fatalities Increase with Shorter Fatality Search Intervals

Abstract

Wind turbine collision fatalities of bats have likely increased with the rapid expansion of installed wind energy capacity in the USA since the last national-level fatality estimates were generated in 2012. An assumed linear increase of fatalities with installed capacity would expand my estimate of bat fatalities across the USA from 0.89 million in 2012 to 1.11 million in 2014 and to 1.72 million in 2019. However, this assumed linear relationship could have been invalidated by shifts in turbine size, tower height, fatality search interval during monitoring, and regional variation in bat fatalities. I tested for effects of these factors in fatality monitoring reports through 2014. I found no significant relationship between bat fatality rates and wind turbine size. Bat fatality rates increased with increasing tower height, but this increase mirrored the increase in fatality rates with shortened fatality search intervals that accompanied the increase in tower heights. Regional weighting of mean project-level bat fatalities increased the national-level estimate 17% to 1.3 (95% CI: 0.15–3.0) million. After I restricted the estimate’s basis to project-level fatality rates that were estimated from fatality search intervals <10 days, my estimate increased by another 71% to 2.22 (95% CI: 1.77–2.72) million bat fatalities in the USA’s lower 48 states in 2014. Project-level fatality estimates based on search intervals <10 days were, on average, eight times higher than estimates based on longer search intervals. Shorter search intervals detected more small-bodied species, which contributed to a larger all-bat fatality estimate.

Post-construction bird and bat fatality monitoring studies at wind energy projects in Latin America: A summary and review

“…There was a geographic bias in the number of publicly available PCFM reports relative to the MW of installed capacity. Annual fatality numbers most likely increase with increased installed wind energy capacity [ 44 ] and according to our results, the number of publicly available PCFM reports is not proportional to the MW of installed capacity in Latin American countries. Compared to its installed capacity of 15,452 MW as of 2019 [ 23 ], Brazil was under-represented with only two studies [ 41 , 45 ] from one project (Osório Wind Farm with 150 MW of installed capacity).…”

Utility‐scale solar impacts to volant wildlife

“…Avian mortality at utility‐scale solar projects might contribute cumulatively to an ongoing substantial decline of birds in North America (Rosenberg et al 2019). Bat mortality at solar projects contribute cumulatively to increasingly large nationwide impacts to bats caused by wind turbines (Smallwood 2020). That many of the birds and bats killed at solar projects were special‐status species should heighten concern over the ecological and economic impacts of solar energy‐caused mortality.…”

“…Accurate estimates of wildlife mortality would help determine impacts at project and regional levels. Researchers have calculated regional estimates of wind energy impacts to birds (Loss et al 2013 a , Smallwood 2013, Zimmerling et al 2013, Erickson et al 2014) and bats (Hayes 2013; Smallwood 2013, 2020; Zimmerling and Francis 2016). Researchers have also discussed cumulative impacts (Calvert et al 2013) and calculated regional estimates of wildlife mortality caused by other anthropogenic sources, such as from collisions with automobiles (Loss et al 2014 a ), transmission lines (Rioux et al 2013, Loss et al 2014 b ), and buildings (Machtans et al 2013, Loss et al 2014 c ), and predation from house cats (Loss et al 2013 b ).…”

“…Accurate estimates of wildlife mortality would help determine impacts at project and regional levels. Researchers have calculated regional estimates of wind energy impacts to birds (Loss et al 2013a, Smallwood 2013, Zimmerling et al 2013, Erickson et al 2014) and bats (Hayes 2013;Smallwood 2013Smallwood , 2020Zimmerling and Francis 2016).…”

An investigation of bat mortality in British Columbia, Canada

“…Trauma was a major cause of death of bats in our study. Trauma commonly impacts bats near wind energy facilities (Smallwood 2020) and through collisions with vehicles (Fensome and Mathews 2016). Although one bat in our sample was killed by trauma at a wind farm, fatalities at wind energy facilities are typically detected via active surveillance, so despite estimates that hundreds of bats are killed by wind turbines in BC every year (Zimmerling and Francis 2016), our study was unlikely to detect them.…”