Re: squirrel stuck in my fireplace
StS gives terrific advice. It sounds as if he might actually be in the fireplace itself and not in the chimney. If this is the case, opening the fireplace door and letting him escape after you have opened your front and back doors and put a treat in the threshold of each might very well work. Every once in awhile a wild gray or red will make its way in at our house (not through the chimney - I am notorious for leaving doors open) and this is the method we use to coax them outside. No harm no foul. Just trust that the squirrel wants nothing more than to be outside.
On the topic of chimney professionals, we installed a spark arrestor at the top when we built the house. The heavy wire mesh that arrests the sparks also keeps all creatures out of the chimney. They remain safe and free and the roof doesn't go up in flames. Your insurance company might even provide you a small premium discount if you install a spark arrestor and let them know.
Good luck. If it does go from the open fireplace door into your house, please do not try to corner it, catch it, or get between it and the open outside doors. It is a wild animal, and it is terrified. Stay safe while helping it by opening the fireplace door gently and silently, and moving away quickly, quietly, and calmly - preferably to another room with a door you can close behind you for a few minutes while it makes its way outside. With the outside doors open, he'll hear and smell his natural habitat and head for it in short order.
Jamie
"some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence