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.
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This study is summarised as evidence for the following.

	Action	Category
	Prevent turbine blades from turning at low wind speeds ('feathering') Action Link

Prevent turbine blades from turning at low wind speeds ('feathering')

A replicated, controlled study in 2005 at a wind farm in an agricultural area of Alberta, Canada (Brown & Hamilton 2006) found that preventing turbine blades from turning at low wind speeds (‘feathering’) resulted in fewer bat fatalities than at conventional turbines. The total number of bat carcasses recovered by searchers was 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). Five bat species were found, although 97% of bat carcasses were hoary bats Lasiurus cinereus and silver-haired bats Lasionycteris noctivagans (see original report for data). In August 2005, all of 39 turbines were operated using conventional methods (blades rotated freely at wind speeds <4 m/s). In September 2005, odd numbered turbines (20 of 39) were braked and locked to prevent them from turning at wind speeds <4 m/s. Nineteen control turbines were left unaltered. Carcass searches were conducted weekly along transects in circular plots (40-m radius) around each turbine in August–September 2005.

(Summarised by: Anna Berthinussen)