Yes, within the past three weeks, all of the chipmunks in my yard, and at least three of my neighbors's yards have disappeared, including one that came daily to eat out of my hand. No new cats around, but a fairly active Coopers Hawk has been raiding our birdfeeders. So either it's a highly efficient chipmunk killer or something else is going on. Collectively, our neighborhood has a lot of both chipmunks and gray squirrels. The hawk doesn't go after the squirrels; they ignore the hawk when it's around.