My appreciation is extended to Professor Richard F. Johnston, who
advised me during the course of this study, and to Professors A. Byron
Leonard and Theodore H. Eaton for critically reading the manuscript.
I would like also to acknowledge the assistance of Dr. Robert M. Mengel
and Mr. Jon C. Barlow for suggestions on procedure, and Mr. William C.
Stanley, who contributed specimens of Mourning Doves for study. Mr.
Thomas H. Swearingen offered considerable advice on production of
drawings and Professor E. Raymond Hall suggested the proper layout of
the same and gave editorial assistance otherwise, as also did Professor
Johnston.