The problem has fixed itself. I was trying to demonstrate the chirp over the phone to an accordion player in Chicago and it didn't chirp and hasn't since then. Go figure. There was probably something in the reed as you suggested. I live in Wisconsin and it is cool in my house, 65 or so. I have not been so foolish as to bring it in from the cold and play in a warm moist house without allowing it to reach room temperature in the case. It hasn't been out of the house since it got too cold to play on the porch. It lives in a room in the case along an inner wall away from the drafty windows with two other boxes.
Thanks for your help.
Leslie