Book excerpt: From leading ornithologist and bestselling author David Sibley comes this essential write-in field companion for all levels of birders. This indispensable birder's companion includes both ample space for on-site notes and a life list to be filled in by the legions of passionate birders who have bought Sibley's bestselling guides. Included are entries for the 923 species found in the United States and Canada, with space for recording where and when a bird was seen and for notes or memories about the sighting. At the back is a complete checklist of all the birds for building the life list.