The Sound Approach to Birding: A Guide to Understanding Bird Sound.—Mark Constantine and The Sound Approach. 2006. The Sound Approach, 29 High Street, Poole, Dorset BH12 1AB, United Kingdom. 2006. 192 pp. + 2 CDs. Bird and habitat photos, ≈160 sonagrams. ISBN 10:90-810933-1-2. ISBN 13:978-90-810933-1-6. NUR code: 435. £29.95.—What is the “Sound Approach”? It is a trio of enthusiastic bird-sound recordists-analysts (Arnoud B. van den Berg, Mark Constantine, and Magnus Robb) who, with friends, traveled to 42 countries in a massive effort to record all the songs and calls of the birds of the Western Palearctic. The recordings in this guide are selected from the 30,000 or so recorded digitally with stereo microphones by the authors since the year 2000.

Part 1 describes the essentials of tone and timbre, pitch and frequency, and rhythm and timing. The first example given of the importance of sonagrams (pictures of the actual sounds made by the bird) is the failure of field-guide authors to describe verbally the differences between calls of the four species in the genus Pluvialis. This caught my attention because I was familiar with calls of all four. In fact, I was once astonished when a European Golden-Plover (P. apricaria) that was flying over the Scottish Isle of Rhum responded to my imitation and landed at my very feet. I had never been able to whistle a satisfactory imitation of a Pacific Golden-Plover (P. fulva) or an American Golden-Plover (P. dominica).

From Part 2 through the final Part 10, annotated sonagrams adorn nearly every page, occasionally interspersed with photographs of birds and habitats. Species are grouped according to similarity of songs or calls rather than by taxonomic relationships. Instead of editing out extraneous sounds, the sonagrams are reproduced in their entirety. When other species are singing on the same cut, the song of the target species is displayed in red and the songs and calls of other species are identified where they appear. Both the CDs and the sonagrams are amazingly clear of traffic and other mechanical noises.

The sonagrams are not all to the same scale, those extending to 12 kHz being slightly compressed vertically. I applaud the authors for using a 0-kHz base for all. They are typically 3–10 s in length, with extremes of 1 and 34 s, the latter for a Common (Great Northern) Loon (Gavia immer). The sonagrams appear in the same sequence as on the CDs, making it easy to match sight and sound.

The chapter headings hopefully make more sense to a European reader than to me, but the frequent subheadings are descriptive and reveal much of the book's content. A few examples: Simple song; Kite and pipit calls illustrate modulation; Separating stonechats by inflection; Gull long calls; Comparing woodpecker drums by oscillogram; Learning to sing; Plastic song; Mimicry, hybridization, mixed singers and dialect; No bird has just one call or one song.

Clearly, this book was designed for a European audience. Its chief values to Western Hemisphere readers are (1) to show how sonagrams can help in the understanding of bird vocalizations, (2) to teach us to recognize vocalizations of European birds, and (3) to help us distinguish by voice a few species that occur on both sides of the Atlantic: Common Moorhen (Gallinula chloropus), Golden-Plovers, Pectoral Sandpiper (Calidris melanotos), Herring Gull (Larus argentatus), Lesser Black-backed Gull (L. fuscus), Common Tern (Sterna hirundo), Arctic Tern (S. paradisaea), European Starlings (Sturnus vulgaris), crossbills (Loxia spp., 15 pages), and some male versus female waterfowl.

The authors devote four pages to distinguishing various calls of Arctic Terns from those of Common Terns. The simplest way is by the long call, which speeds up toward the end in the Common Tern, but in the Arctic Tern consists of a few staccato notes alternating with a longer one. The kee-arr advertising call of the Common Tern is a little slower, lower, longer, and more mellow than the harsher, shorter, and more hurried irr of the Arctic Tern. The scolding gyarrrr call is slightly lower-pitched in the Common Tern, but the difference is really noticeable only in the fundamental frequency of the start of the call. The kip calls are higher-pitched in the Arctic Tern. These differences are clarified by the sound recordings and sonagrams.

A list of the species on the CDs, in the sequence in which they appear, is in the front of the book; details of location, date, age, sex, background species, and catalogue data are included on the pages with the sonagrams. Three pages of References and the Index complete the volume.

Americans have been slow to recognize the identification value of sonagrams. This volume should encourage many of those who have paid no attention to songs and calls as a means toward identification to reconsider their virtues. In spring and summer, most birds are heard before they are seen, and many are not seen at all. Songs and most brief call notes are diagnostic. Although I do not predict that this book will be a bestseller in the Americas, it will be a classic in its field. It will be sought by serious birders eager to hone their identification skills and by taxonomists interested in comparing geographic differences in bird vocalizations. Therefore, copies should be available in public and school libraries as well as in university libraries.