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Providing evidence to improve practice

Individual study: Monitoring of bird and bat collisions with wind turbines at the Summerview Wind Power Project, Alberta, 2005–2006

Published source details

Brown W.K. & Hamilton B.L. (2006) Monitoring of bird and bat collisions with wind turbines at the Summerview Wind Power Project, Alberta, 2005–2006. Vision Quest Windelectric report.


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Prevent turbine blades from turning at low wind speeds to reduce bat fatalities Bat Conservation

A replicated, controlled before-and-after study in 2005 at a wind farm in an agricultural area of Alberta, Canada (Brown & Hamilton 2006) found that preventing turbine blades from rotating at low wind speeds resulted in fewer bat fatalities than at conventional control turbines. The total number of bat carcasses recovered by searchers was significantly lower at experimental turbines shut down at low wind speeds (64 bats, 40% of total) than at conventional control turbines (95 bats, 60% of total). The number of bat carcasses did not differ significantly between turbines before the experiment (‘experimental’ turbines: 157 bats, 49% of total; ‘control’ turbines: 164 bats, 51% of total). In August 2005, all of 39 turbines were operated using conventional methods. In September 2005, odd numbered turbines (20 of 39) were braked and locked to prevent them from turning at low wind speeds (<4 m/s). Nineteen control turbines were left unaltered. Carcass searches were conducted weekly along transects covering a 140 m2 area around each turbine in August–September 2005.

(Summarised by Anna Berthinussen)