This, incidentally, is why I don't take people who make the "wind turbines kill birds" argument seriously. It's not false, but the number is very small compared to those killed by domestic cats and window collisions. So the loss is minimal provided they're not in a breeding area for an endangered species.
>Current research suggests that the overwhelming majority of bat fatalities are caused by collisions with turbine blades. There is some evidence to suggest that a phenomenon known as barotrauma may result in a small proportion of bat deaths, as well. Barotrauma involves tissue damage to air-containing structures, such as lungs, caused by rapid or excessive pressure change. Air pressure changes can occur at the edges of moving turbine blades and may help explain some bat fatalities.
>Between 2000 and 2011, an estimated 650,000 to 1.3 million bats have died from collisions with wind turbines in the United States and Canada (Arnett and Baerwald 2013). Additionally, as many as 400,000 estimated fatalities may have occurred in 2012.
>in the U.S. and Canada, at least 24 species of bats have been reported as killed by wind turbines. The hoary bat (Lasiurus cinereus), eastern red bat (Lasiurus borealis) and silver-haired bat (Lasionycteris noctivagans), all migratory tree bats, account for nearly 78% of the kills north of Mexico. The hoary bat accounts for 38% of the fatalities. A new study that looked at hoary bat mortality at wind energy facilities during 2014 revealed that populations of the species may plunge by a staggering 90 percent in the next 50 years if no action is taken.
>At some sites in the Midwest and Eastern U.S., species that are already battered by White-nose Syndrome (WNS), can account for up to 60% of wind-energy fatalities.
Two federally endangered species, the Hawaiian hoary bat (Lasiurus cinereus semotus) and the Indiana myotis (Myotis sodalis), also have been killed by turbines.
This is not a good argument given that the victim populations typically are different species. The hawk population cares about cats eating songbirds just in so far that it removes some of their own food supply, not because it is threatened by cats.
There is also a big quality difference. Turbines kill raptors, eagles, storks and vultures. And some hunters kill huge amounts of migratory birds. You need to put all things together.
Birds know well that cats are dangerous. The real problem is the habitat loss and pesticides. The first force birds to nest in dangerous suboptimal places, where cats can catch them. The second makes them much more vulnerable to cats.
My understanding is that the idea that wind turbines kill birds in huge numbers is based on the original wind turbines. These were much smaller in radius and had many more blades and spun much faster.
Think of a giant farm water-pump windmill. Those things were bird blenders. Modern three blade wind turbines are a different beast, but many people have not caught up with the changes in engineering.
[ Also, some of the initial wind farms using the bird blenders (e.g. the Altamont Pass near Livermore, CA) were right on the Pacific Flyway, which is a massive migratory path. ]
I'm also thinking that birds will adapt because it seems like a relatively simple change in their behavior would fix the problem. Natural selection will play its course. The birds who are dumb enough to fly into wind turbines will get weeded out. Future generations of bird will be more fearful of wind turbines. This kind of selection can start to take place over a relatively short span of time. See peppered moth evolution [1].
How long would it take for natural selection to play its course though? Moths live for maybe a year, while a bird might live for a few decades.
And the soot from the industrial revolution would've covered the entire environment for a peppered moth, whereas many birds fly over incredibly large distances, which wind turbines will only cover a small fraction of.
