1975 1st edition thus. Falconiforme Press Ltd. Saskatchewan, Canada. Stapled paperback. Pp45. B/w illustrations, maps, charts. Blue pictorial wrappers. Owner's label inside, small hole to rear cover else very good.
Notes: A reprint of Frank Beebe's original article which appeared the The Condor, Volume 62, Number 3 May-June, 1960. A superb and in-depth work spanning field research undertaken between 1949 and 1958 with subsequent conclusions - research which is still frequently cited in contemporary articles.
