Like its parent set, the new edition of Grzimek's adheres to a taxonomic arrangement. Following a set of essays on topics such as bird song and migration, material is arranged by class, then by order, then by family. For each family, entries are headed with summary data on details such as size and numbers of genera and species. Following this are standardized sections on evolution, physical characteristics, distribution, habitat, behavior, diet, reproduction, conservation status, and significance to humans. Entries conclude with species accounts that list key facts on selected species and further resources. Distribution maps, approximately 480 color photographs depicting birds in natural settings, and more than 1,300 very attractive illustrations of featured species accompany the text. One slight disappointment is the photographs, which are nice enough but nothing special, especially compared to those in Grzimek's Encyclopedia of Mammals. Each volume winds up with the same back matter: a bibliography, a list of bird-related organizations, a list of contributors to the first edition of Grzimek's (some of whom also contributed to the second), a glossary of bird terms, an "Aves Species List," and an index to all four bird volumes.