Estimates about bird deaths from wind turbines vary greatly, but opponents of wind turbines, like fossil fuel industrialists and owners of golf courses, generally estimate on the high side.
I found a Smithsonian article that states that we kill between 140,000 and 328,000 birds a year in the United States with wind turbines. This is based on a study searching for the results of many other studies. We will never be able to have an exact number, but this is pretty close.
However, there are many causes of deaths for birds that are much more devastating. Supposedly, for every bird killed by a wind turbine, 2,800 birds are killed by cars. I certainly have hit my share of birds over the years. Critics often point out raptor birds as the victims, because those are the cool and rare ones. Researchers have identified the leading causes of deaths of raptors to be (1) shooting, (2) poison and (3) cars.
The leading causes of deaths for birds are buildings, power lines, cats, automobiles and pesticides, in that order. One study actually found that feral cats alone kill 3.7 billion birds in the United States every year. That is 10 million birds a day. Compare that to the estimated 2 per day per wind turbine.
No matter what study you believe, and what numbers are accurate even by a factor of 100, claiming that wind turbines should not be used to reduce killing of birds makes no sense whatsoever.
But then, there is Trump.