04:06 PM

New Study Sounds the Alarm on Hoary Bats, Highlights Need for Swift Action


Contact: Catalina Tresky: (202) 772-0253 or ctresky@defenders.org


WASHINGTON (Feb. 24, 2016) – A new study published in Biological Conservation found that the hoary bat population in North America could decline by 90 percent in the next 50 years if actions are not taken by wind energy facilities to reduce current high rates of mortality. These results highlight the urgent need for the development and wide-spread adoption of conservation strategies to sustain viable hoary bat populations.

Jamie Rappaport Clark, CEO and President of Defenders of Wildlife, issued the following statement:

“When it comes to wildlife conservation, we rarely have the opportunity to save a species before emergency measures are required. This new study is a clear warning signal that action is needed before the hoary bat population plummets and needs heroic measures to prevent its extinction.

“Defenders of Wildlife will work with the wind energy industry and other conservation partners over the next year to tackle this issue, so that these dire predictions never become reality. Fortunately, the solutions necessary to save this species appear to be within reach. Promising research is underway on strategies to prevent bat mortalities at wind energy facilities such as ‘turning off’ wind turbines when bats are most active and using high frequency sounds to deter bats from turbines. We will work to increase investments in these research efforts and hope to drive the adoption of effective conservation strategies industry-wide to save bats and secure a future for wind energy production.”


Hoary bats have the widest range of any North American bat — extending from Argentina and Chile to northern Canada. In the United States, they live in the pine-hardwood forests of the East and in arid deserts and ponderosa pine forests in the West. They are most abundant, however, on the edges of croplands and deciduous forests of the Plains states and in coniferous forests of the Pacific Northwest.

The new study by Winifred Frick and others examines the long-term impacts of wind turbine fatality rates for the hoary bat (Lasiurus cinerus), including effects on population size and risk of extinction for the species. In North America, hoary bat is the migratory bat species most frequently killed by turbines. For 2014, the authors estimate the turbine-related fatality rate for the species at 128,469 hoary bats/year based on prior published data. Assuming that the estimated proportion of the population killed by turbines in 2014 continues unchanged into the future, and considering expert estimates for current population size and growth rate, the authors modeled a precipitous decline in the hoary bat population over the next 50 years.

The results from this new study suggest that, without meaningful additional measures to minimize fatalities, there is a realistic possibility of substantial population decline and increased risk of extinction for the species due to wind turbines. The authors note that the expansion of wind energy capacity would be expected to increase fatalities and cause even greater impacts to the species. Fortunately, there is promising research on operational changes and new technologies to significantly minimize bat mortalities from wind facilities. These include turning turbines “off” during the late summer-fall migration period when bats are most active and deterring bats with high frequency sounds, ultraviolet light, and specialized coatings on the turbine monopole. Increased research investment is critical to validate and commercialize these measures and technologies as soon as possible.

Defenders believes strongly that conservation organizations and the wind energy industry need to work together if we are to address the serious threats of climate change by facilitating responsible wind energy development without jeopardizing our country’s precious wildlife resources. Americans do not have to choose between reducing our greenhouse gas pollution and protecting our rich wildlife legacy from energy development.


Defenders of Wildlife is dedicated to the protection of all native animals and plants in their natural communities. With more than 1.2 million members and activists, Defenders of Wildlife is a leading advocate for innovative solutions to safeguard our wildlife heritage for generations to come. For more information, visit www.defenders.org and follow us on Twitter @DefendersNews.