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Scare-O-Trauma: A Hoary Bat Story

Original Photo by Daniel Neal, Oregon State University. Edits made by Kendall Burke.

Halloween is just around the corner and with it comes all of the bloodcurdling terrors of the night. So it’s time to put on your bat wings and hit the streets to show that you are the most adorable of them all: the small but helpful hoary bat. 

The hoary bat (Lasiurus cinereus) is a small migratory tree bat that ranges throughout the entirety of North and South America. Being a non-colonial tree bat, the hoary bat lives in isolation during its spring and autumn migratory period, where it pursues resources such as roosting locations, prey (primarily moths), and mating opportunities. During its wintering period a significant segment of the population aggregates along California’s coast.

The development of wind turbine facilities throughout the United States has generated a substantial issue for the hoary bat and other migratory bat species. Recently published studies have directly linked wind turbines to an exponential increase in mortality of hoary bat populations, with expert opinion establishing the species may become extinct within the next 50 years. Hoary bats are susceptible to colliding with turbines due to their roosting and migratory behavior, which causes an attraction to tall objects like wind turbines. Fatalities occur due to either direct collisions or a condition brought on by a rapid change in pressure, which results in mortality called barotrauma. Luckily, there’s a solution. Hoary bats are most at risk during a very small window of time: during their migration period, particularly at dawn and dusk with low wind speeds. If we don’t spin turbines at these times, studies have shown a radical reduction in bat mortality (between 50-90%!) with only minimal losses of power (1-3.5% of total energy generation). 

Sounds like an easy solution, right? Despite a clear way to mitigate impacts upon the population there is a distinct lack of implementation. The wind energy industry has balked at voluntary protection measures because the bat is not yet listed under the Endangered Species Act.

So in the spirit of Halloween, support our little friend and put on your wings. You and your hoary friends don’t have a sweet fang for candy, hopefully there are king size moths handy.  With the arrival of Autumn means it’s time to migrate, so travel safe and don’t forget to echolocate! And be careful around wind turbines, because you don’t want any scare-o-trauma. 


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