The National Geographic Illustrated Birds of North America Folio Edition presents illustrations and descriptions for 967 North American bird species. The main text includes both native and accidental species, with some extremely rare (or extinct) species in an appendix. Illustrations are largely the same as in previous editions of the guide but are enlarged to show more detail. I cannot compare these illustrations to the 5th edition of the field guide, but they appear very similar to those in my 1st edition. Range maps have been revised and enlarged.
This edition updates the taxonomy to reflect recent changes made by the American Ornithologists' Union. Thus the Saltmarsh Sparrow and Nelson's Sparrow have "Sharp-tailed" deleted from their names. Cackling Goose is presented as a separate species. Tanagers are not grouped together with cardinals and grosbeaks, but the introduction makes note of their reclassification. Scientific names, such as the genera of gulls and terns, are also updated.
National Geographic's Birds of North America stands with the Sibley Guide to Birds and the Peterson Field Guide to the Birds of North America as one of the best choices for birders who prefer that their field guide have painted illustrations rather than photographs. Unlike the Sibley and Peterson guides, the National Geographic guide eschews static illustrations that show all related birds in the same pose for more naturalistic illustrations. Birds are shown in a variety of poses, often with hints of their native habitats or food sources. National Geographic's illustrations show more detail than Peterson's and have more subtle colors than Sibley's.
When I am using a guide in the field, I much prefer that the illustrations show consistent poses. This makes it much easier to find points of comparison quickly. However, National Geographic's naturalistic illustrations come into their own in this folio edition. The larger size makes it easier to appreciate Dunn and Alderfer's work to put the birds into context. The implied action in many of the poses and inclusion of habitat details recall the work of John James Audubon, even though Dunn and Alderfer's work is technically superior (and more scientifically accurate). In the case of the Peregrine Falcon, the illustration in the National Geographic guide seems like a direct reference to one of Audubon's engravings, as each book shows a falcon clutching a dead Green-winged Teal.
The National Geographic Illustrated Birds of North America Folio Edition is a high-quality book with excellent illustrations. I will leave it to readers to decide if the correspondingly high price is worth paying; my guess is that for owners of the field guide's 5th edition, the answer is probably no. However, it could be a complementary reference for owners of other field guides.