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Providing evidence to improve practice

Individual study: Red aviation lights on wind turbines do not increase bat–turbine collisions

Published source details

Bennett V.J. & Hale A.M. (2014) Red aviation lights on wind turbines do not increase bat–turbine collisions. Animal Conservation, 17, 354-358

Summary

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Remove turbine lighting to avoid attracting bats

A replicated, controlled study in 2009-2013 of wind turbines in cattle-grazed pastures in north-central Texas, USA (Bennett & Hale 2014) found that when wind turbines had red flashing aviation lighting bat fatality rates were lower than those without lights. Overall, the average number of bat carcasses/search was 0.0280 at turbines with lights compared to 0.0550 at those without (total 916 bats). However, this pattern was led by the eastern red bat Lasiurus borealis (lighting: 0.0159; without: 0.0343 carcasses/search, n = 551). There was no significant difference in fatalities between turbines with and without lighting for hoary bats Lasiurus cinereus (lighting: 0.0080; without: 0.0140, n = 258), tri-coloured bats Perimyotis subflavus (lighting: 0.0013; without: 0.0031, n = 22), evening bats Nycticeius humeralis (lighting: 0.0014; without: 0.0009, n = 4) and Mexican free-tailed bats Tadarida brasiliensis (lighting: 0.0001; without: 0.0020, n = 30). The 48 km2 site of cattle-grazed pastures had 75 wind turbines (80 m tower, 42 m blades, 1.5-MW), of which 23 had Federal Aviation Administration lighting (red strobe, 30 pulses/minute, 2,000 candela) and 53 did not. Bat fatalities were recorded from July to October (during migration) in 2009-2013 at wind turbines with (3,049 searches) and without red aviation lighting (10,555 searches). An area of radius 35-65 m from each turbine was searched each 1-6 days. The date, species (confirmed by DNA), and the bearing and distance from the turbine was recorded for each carcass found.   (Sarah Lakke)