Fifty-six of these species are placed in a "Rarities" section that includes accidentals, rarer pelagics, and species that have not been reported in more than twenty years. The detailed full-color illustrations show identifying features--including plumage differences among males, females, and juveniles--and views of birds in flight wherever pertinent.
Robert Dean has supplied more than 360 new illustrations, including sixty-four species that are illustrated for the first time in this edition. These include recent additions to the country list, pelagic species, Cocos Island species, and all accidentals recorded from the Costa Rican mainland. Range maps and nomenclature have been updated for this edition, which also has a new user-friendly organizational scheme and an alphabetical quick-find index of groups on the inside back cover.