This classic monograph on Campephilus principalis by James T. Tanner was first published in 1942 by the National Audubon Society, USA. An unabridged edition (cover shown here) was published by Dover Publications Inc., New York, in 2003.
This very variable species is currently composed of 19 races across central and south America. It has had a rather confusing taxonomic history, formerly placed in the Piculus genus and with some races regarded as species in their own right.
This book examines the history of the declines of two of the world's largest woodpeckers: Campephilus imperialis and C. principalis. The causes of decline and the question of whether these birds are extinct or not is discussed in detail. The authors (Noel F. R. Snyder, David E. Brown and Kevin B. Clark) take the view that these species are sadly extinct. Published in 2009 by the University of New Mexico Press, USA.