I had a raccoon come down my chimney (which is now capped!!) a few years ago, and she gave birth to her babies there. When I called Colorado Fish & Game, they told me studies said I should try a radio. When I asked which station they preferred, he just laughed. (This was all after he first recommended that I just run out and get myself some fox urine.)
I've always wondered how much of my tax dollar funded the study.