1973, Unabridged republication of the original 1962 edition. 343 pp. Paperback in Very Good condition. Corners are slightly rubbed, but not quite bumped. Some wear on the top and bottom of the wrappers, but no major flaw present. Text block is clean, crisp, and without flaw. Revised and enlarged by the author. 25 photographs. 43 other illustrations. List of references. Indices. Two lists of addenda. This is a book that should be required supplementary reading for courses in ornithology and bio-acoustics and a book that will do much to answer questions and further appreciation of bird behavior and the songs of the birds.