Recommended readings on: bird songs and territoriality-Frank Gill “Ornithology” published by W.H. Freeman and Co.; Fitness and mating behavior-John Alcock “Animal Behavior” published by Sinauer Associates Inc.; Bird behavior-P.R. Ehrlich et al. “The Birder’s Handbook published by Simon and Schuster, D.A. Sibley “The Sibley Guide to Bird Life and Behavior” published by A.A. Knopf and; D.W. Stokes “A Guide to Bird Behavior” Vol. 1-3 published by Little Brown and Co.