"Photographing Birds" is a pocket-sized book aimed at covering the full gamut of bird photography from equipment to a short list of places to take photographs of birds. In between, chapters include luring and stalking birds, photographing nesting and flight and special challenges like night photography and winter photography.
This book is apparently an update of a previous National Geographic book entitled "National Geographic Photography Field Guide: Birds". While I did not read that prior volume, this book has the feel of a job of cutting and pasting. For example, in the Getting Started chapter, there is an extensive discussion of film in the main text and then some sections that feel like they had just been appended on digital photography. The same section contains a discussion of catadioptric (mirror) lenses. No bird photographer I know would consider using such a lens today.
Two of the basic problems that any bird photographer will face are exposure and focus. There is no discussion in this book of how one might compensate for different lighting conditions and bird tonalities. There is a reference to the histogram, one of the most useful devices that digital SLR cameras offer for the control of exposure, but no explanation of this function. With regard to focus most modern cameras offer a choice between single focus and continuous focus and the selection of one or the other can greatly affect the images taken, but there is virtually no mention in this book.
The basic shortcoming is that while the book recognizes the problems of bird photography, there is very little practical advice. Even such a basic subject as depth-of-field is not included in the book.
For several years the gold standard for bird photography has been "The Art of Bird Photography" by Arthur Morris. It doesn't cover digital photography but it's still a lot more useful than this book. Morris has an e-book on digital bird photography which is available from his web site, but which he is not yet offering in a printed version.
The bottom line is that I cannot recommend this book for any photographer.