Date: 9/4/20 6:34 am From: Steve Long <steve.long4...> Subject: Re: [MDBirding] Painting wind turbine blades black to decrease bird hits
At least it is a start to ask how birds perceive (or misperceive or
don't perceive) wind turbine blades.
Having black blades probably helps noticing them against a light sky,
because the birds are probably biologically geared to notice motions
that might be attacks from flying predators, at least during the day.
But, windmill blades also move at night and during dense fogs over land
and the ocean waters, when and where there are sometimes mass
migrations. Not siting windmills in such locations may be difficult,
because first, the migrations are following long paths, and second,
those paths can shift laterally by large amounts due to winds and other
factors. The precise timing of migrations is also not fully
predictable. And, the migrating birds are also probably "playing the
winds" to facilitate their travels.
So, it may be most practical to require wind farms in the vicinity of
known migration paths to stop their blades for the whole periods when
migrations are known to occur. A requirement like that would naturally
have the tendency to favor siting wind farms well away from important