More people that guesses, but no one still knows the source of this perplexing pigmentation. Most seem to react to leave the Snowy alone, so we will likely never know the answer. Check out the new commentary in the article.
My wife's work computer desktop background changed itself today, and she called me in to see it. I said, "that's a Saw Whet." Not believing me, she looked up the credits and said, "get out! It is!"