New data suggest that bats, like birds, may follow specifically defined routes when migrating rather than simply migrating in a dispersed way across a broad area. Wind energy turbines located in these routes may cause fatalities of migrating bats.

As new sources of energy such as wind farms are being built in greater numbers, their impact on other aspects of the environment are getting attention.

The migratory behavior of bats, a topic that has received little attention in the past, is the subject of new study. Wind turbines have been the cause of many bat fatalities, but these installations also offer a new opportunity to examine bat migration habits. This is because the majority of bat fatalities caused by wind turbines around the world have involved migratory bats during fall migration.

Over a period of seven years, scientists used acoustic monitoring and carcass searches at nine wind energy facilities across southern Alberta, Canada, to determine if bat activity and fatality were concentrated in certain areas or evenly distributed across the landscape. Their findings indicate that as bats migrated, they concentrated along selected routes at night and sought daytime roosting sites. Migratory tree-roosting bats, including hoary bats, eastern red bats, and silver-haired bats, are the North American species most affected by wind farms.

The full text of this article, “Geographic Variation in Activity and Fatality of Migratory Bats at Wind Energy Facilities can be read at www2.allenpress.com/pdf/mamm-90-06-1341-1349.pdf.