It last happened in November, 2014. A ruffed grouse went into the window. I suspect the hawk chased it. There is a pair of red-tailed hawks checking out the old horned owl nest just across the street. They have not nested there, but I hear them a lot. We have a sharp-shinned hawk in the area, as well.
It happened again, on May 1st, 7:45 a.m. I wrapped it in a towel to see if it would recover. It did not. I held it until it was gone. It was a massive hit.
I put the little body on the far lot. Some creature would benefit from it. Either the vultures or the coyotes.