Just to update everyone on the white pigeon: After spending the night in my roof gutter, it heartily fed itself next day, but resisted to be caught. Later that day, it flew off and has not returned since. I can only think that it came to wish me Happy Birthday, since it was my birthday yesterday, and now that the big day is over, it has possibly gone home, or simply chosen freedom. Whichever way it was, it was a half-century birthday present that I won't forget. My husband says that pigeons are very clever birds.