From Rita at Res Ipsa, how to fish for squirrels.
In college I spent a year and a half living in a godforsaken downtown YMCA. There was plenty of atmosphere - bums, a porn store, a hotsheet joint and a narrow alley where you might occasionally catch a hooker earning her fee on the fire escape. But at night, before the winos came back to the alley, I heard it had some pretty good rat fishing from the fourth floor roof.
At first I thought my buddies were pulling my leg, but no - they were even shown on the front page of the campus newspaper with a big stringer of rats.