Another interesting feature of the guide is the inclusion of a bird song DVD with vocalizations for 138 species, totaling 587 mp3 files. The files are intended for download onto a portable mp3 player, which I suppose is a sign of the ubiquity of these devices in birding culture (although I have yet to pick one up). While the inclusion of the DVD is a great idea, I do agree with other reviewers that it would have been more useful to include sound files for ALL of the species in the guide, at the sacrifice of the variety of vocalizations. The DVD includes many very common species, but there’s some weird omissions – Willow Flycatcher is included, but none of the other common Empidonax flycatchers that are virtually indistinguishable from Willow Flycatcher – except by voice! I think that while the idea is great, by not including an mp3 file for every bird in the book, the concept falls flat. It’s nice to have the short perch songs, dawn song, dawn flight song, and calls from two different regions for Tree Swallow, but the limited number of species on the disc just makes it more frustrating than useful for the experienced birder. The beginning birder, though, might find the disc far more useful, since the multitude of calls included for common species may be very handy in developing the skills of birding by ear.
I personally am going to stick with Sibley’s regional guides for my main field guides, but I think that the Smithsonian field guide will make an excellent back up field guide. The photographs are much clearer than the paintings in the National Geographic guide, and this guide is the equal of the National Geographic guide in everything except for comprehensiveness.