To quote the skeptical environmentalist Bjorn Lomborg - cats kill non-endangered species like sparrows, Jays etc. They do not kill large raptors (they actually kill cats) - wind turbines are a major threat to the larger and more endangered species.
Large soaring raptors can be seen to “suicidally” circle wind turbines for no apparent reason. It is thought that the raptors pick up on the wingtip vortices and cruise around in them looking for a free “lift” as they do for thermals. Clearly seen in the video link below…..
https://www.youtube.com/watch/na6HxKQQsAM
Theoretical wake vortex of a wind turbine.
Actual wake vortex made visible by unusual weather conditions.
Glider pilots will tell you they share the airspace with soaring birds (modern gliders have better “sink” rates than birds) and you can watch them adjust their flight to remain in the thermal and the glider pilot following his variometer finds himself flying the same course as the birds.
A soaring bird crossing the downwind vortex trail would, on exiting an area of lift will turn back in to it and on subsequent crossings reverse the direction of turn – by this navigation method it zig zags or circles up towards the turbine. Once the bird passes the turbine it turns once again to find the “thermal” it was using. This then becomes the “suicidal” behavior we see.
Clearly the fatal footprint of a wind turbine is very much larger that the physical space it occupies.
It has recently been discovered that birds flying in typical “V” formations do so for reason of energy conservation – stealing a little bit of lift from the wing vortices of the bird diagonally ahead – this behavior was previously thought to be a line of sight issue.
This behavior is typical for large migratory bird species – also at risk from the presence of wind turbines.
Migratory birds travelling over water typically adjust their flight paths to fly over islands to gain the benefit of any thermal lift. An offshore wind turbine would look like a tree, obviously must be supported by an “island” – so they adjust their flight path – through the rotating turbine which in most cases are large enough to transect the typical flight altitude of migratory birds. Again birds adopt these altitudes to best make use of thermals and conserve energy.
The above behavior patterns explain the disproportionate mortality for larger birds, particularly large soaring birds like raptors and migratory species.
Wind power is endangering species that have survived numerous ice ages, sea level changes etc - Global Warming poses no threat to them - Wind Turbines are positively lethal - refer the following link that suggest that environmentalists are in a state of denial over this inconvenient truth.
http://www.spectator.co.uk/features/8807761/wind-farms-vs-wildlife/
This by an Oxford professor of ornithology and an expert on species extinction.
Refer to the following article in which windpower companies are using bird mortality figures and sampling guidelines for 50-60m high wind turbines on 100-130m wind turbines in order to “gloss over” the damage being done to bird (and particularly raptor) populations. They also indulge in wishful thinking such as 30 day periods between surveys when they know from other studies that most carcasses are removed by scavengers within 10 days thus underreporting avian mortalities by anywhere from 2 to 10 times the real values.
Wind turbines kill up to 39 million birds a year! - CFACT
The Irish Sea is festooned with offshore wind farms and sea bird numbers have fallen drastically – the greens are in denial and are trying desperately to find some other plausible cause – preferably finding some way of blaming man/climate change as the cause.
Admittedly causality remains unproven but a drop of 50 to 80% in some seabird populations, concomitant with the growth in offshore wind farms, is certainly alarming.
As Wind Farms Overwhelm The Irish Sea, Isle Of Man Seabird Populations Plummet
There's always more to any argument than that propounded in the sales brochures.
And yes this topic is probably better on another forum - so that's it from me.
Regards, Ken
