Donna Posont is living proof that you don't have to be able to see well to go bird-watching. Donna Posont is a field guide in Michigan who leads a group of blind birdwatchers and helps them recognize birds through sound. / CBS News The Field Services Director for Opportunities Unlimited for the Blind, Donna Posont runs a "birding by ear" class in Dearborn, Michigan for people who are blind or who have low vision. Instruction begins inside, where participants memorize bird calls through learning words that have been assigned to birds' chirps and screeches. Armed with a repertoire of  bird