An essential field guide companion for the avid birdwatcher covering
species pairs or groups that are difficult to identify.
This book covers difficult identification issues by looking at tricky
species pairs or groups of birds, and comparing and contrasting their
respective features. Designed as a field companion, it supplements the
standard field guides and provides much additional information. As well
as detailed texts, the books include extensive illustrations of all
relevant ages and plummages of the species concerned.