Wind power has only a small impact on the environment, and the area it is spread out over is largely empty. The environmental impact is minuscule.
The environmental impact of wind is still being studied, however the turbines are not very attractive nor quiet when you are near one, and as you say they are spread over a very large area. There is early evidence that the sound of the turbines does cause stress to wildlife. http://www.ncbi.nlm.nih.gov/pubmed/24597302.
It is known that animals also avoid power line corridors (very unfortunate as these are typically considered as beneficial animal corridors during environmental assessments). http://www.theguardian.com/environment/2014/mar/12/animals-powerlines-sky-wildlife.
The impact of animals avoiding large areas of wind farms and crossing the new power lines is unknown however probably not miniscule.
Nuclear is far better understood as well as far more localized. The newer reactors are much safer than the ones that failed in the past. Even after a disaster the animals are thriving. http://www.csmonitor.com/Science/2015/1011/Wildlife-thriving-in-abandoned-Chernobyl-zone