This set of five compact disks contains 931 separate recordings covering 316 species from the Pacific Northwest. This area is not defined, but to judge from a map on the back cover of the booklet it includes southwestern British Columbia, all of Washington and Oregon, the canyonlands of southwestern Idaho, and about a 100-mile swath of northern California. Each species receives its own track. Each track begins with the species’ name, and individual cuts within each track are separated by a brief pause.