wind energy controversial? still?

Thanks to AWEA for posting this article about a "controversial" wind farm in Wisconsin. As a fan of modern minimalist design, I suppose I'll never be on the same page about wind turbines being "ugly" (to me they're kind of a benchmark of beautiful design), and I've never heard a "jet engine" sound come from any so much as a heavy whooshing one. [ I am willing to stand corrected on that, since NC is wonky and I've never spent an extended amount of time near one. ]

One of the consistently frustrating things for me, as one interested in renewable energy technology, is the lack of quantification behind the claim of increased bird deaths. This article illuminates the data:

Since the turbines started spinning, the state Department of Natural Resources says it has recorded bird and other wildlife deaths attributed to the wind farm at a higher-than-average rate.

Dave Siebert, director of the DNR's energy office, said the national average for wind farms is slightly more than two bird deaths annually per wind turbine. As many as 10 deaths per turbine have been recorded at Forward.

Certainly, at a wildlife refuge (10/year/turbine) that's a significant amount, but the 2/year national average seems a bit... miniscule compared to other ways birds die, no? Is there no way to modify wind turbines to emit some sound or signal that would be heard by flying creatures within a certain range? The person who figures this out will make loads of money, I suspect.