This is a bonanza for ornithologists, professional and amateur. It is also a unique sort of travel book of America -- some 20,000 miles of traveling taken chiefly by car, but with areas covered by plane, by boat. The periphery of these United States, from New England to Texas to the Olympic Peninsula, with out-thrusts to Newfoundland at the start, Mexico, midway, to Alaska at the finish. Ten weeks- 500 birds. And the purpose- the participants, one American (and what bird enthusiast does not know Roger Peterson's name)- one Englishman. It is a fascinating book, demanding background for full apprecation but giving even the rankest neophyte gilmpnes of the thrill of discovery, of comparison, of hope, as the bird is sought- and facts collected. There were other things too- trees and flowers, animals, places- and above all people. One has brief glimpses of many of our national parks, our wild life sanctuaries- and the conservationists who are their resident geniuses.