When I lived in Carlsbad, I found a tomato on the grill of my BBQ one night. Of course, it was quite the mystery as to how the tomato got there, but the mystery was soon solved when I fired up the grill one night and a mouse/rat came flying out the bottom of the grill.
After moving to Carmel Valley, I get the same thing, a small rat/mouse that visits the grill. And my wife often sees him run past the slider in the back yard.
I worked at a company on the hill directly across the street from the Torrey Pines golf course. They had a section of the wall where these rats lived and they had to remove dead rats from the wall every so often. They even had to leave part of the wall covered with just plywood so they could change the traps and collect dead rats every so often.
So the gist is that mice and rats are commonplace here and just about impossible to get rid of, at least we don’t have those giant roaches they have in other places.