Thursday, April 24, 2014
By Herb Wilson
The bird field guides available today represent an embarrassment of riches. Until the National Geographic Guide was published in 1983, birders had two guides, one by Roger Tory Peterson and one by Chan Robbins, for help in field identification. I cut my ornithological teeth on these two field guides. I well remember the plates in the Peterson guide called confusing fall warblers. Confusing they are.
The classification of the New World warblers is confusing as well. In the past couple of years major changes in our understanding of how these warblers are related have emerged. Many of these insights come from the use of DNA comparisons to assess relatedness. Field guides published in the next few years will have a different arrangement and different scientific names for many of our warblers. As an example, hooded warbler, Wilson's warbler and Canada warbler were thought to be closely related and all were placed in the genus Wilsonia. Recent research shows that hooded warbler is actually closer related to warblers like northern parula and palm warbler, and shares a genus name with these species now. The Canada warbler and Wilson's warbler remain in a different genus.
An extraordinary new field guide will do much to reduce our confusion over field identification and get us used to the new classification scheme of warblers. This book is "The Warbler Guide," written by Tom Stephenson and Scott Whittle. Both are accomplished birders and each brings another talent to this guide. Stephenson is a musician and Whittle is a professional photographer.
This soft-bound book, 560 pages, is a bit large for a pocket but easily fits in a backpack for field use.
The first 100 pages provide an introduction to the use of the guide and warbler-specific tips for identification. Most pages are adorned with uniformly excellent photographs of warblers. This guide has literally hundreds of photographs.
The authors begin with a topographic tour of warblers. The photographs are excellent for showing various feather tracts that are often useful in field identification. Then the authors describe various features to notice on a warbler (with many photos), such as facial contrast, shape, eye-arcs, wing panels and flight-feather edging. A useful section on sexing and aging warblers is provided.
The introductory section concludes with a primer on auditory identification. The authors' approach is perhaps the most innovative aspect of the guide. We learned to identify a male chestnut-sided warbler by its "pleased-pleased-pleased-to-meetcha" song. The authors use a different, more objective approach. Songs are broken into phrases and elements, superimposed on element qualities and speed. Sonograms of songs are a prominent feature.
The authors next provide visual finder guides and a song finder guide to allow an observer to quickly hone in on an identification. A Face Quick Finder has 86 photos of side views of all the faces of warbler species on two facing pages. Similar layouts are provided for sideviews, underviews and oblique views of the full body.
The song finder guide relies on the observer noticing numbers of phrases, the timbre of the notes, changes in pitch and other vocal characteristics to reach an identification.
The bulk of the guide is made of the individual species accounts. Each account begins with a few symbols showing the shape in silhouette, the tail pattern, general color, range map and specific habitat (e.g., tops of trees).
Let's take the Blackburnian warbler account as an example. Ten pages are provided with 50 color photos (along with eight photos of warblers that can be confused with Blackburnian). Pithy text descriptions augment the photos. Two pages, replete with sonograms, describe the songs of this species.
The book will be published July 24. A companion app with sound recordings will appear soon as well. Grab a copy of this guide in time to help with those confusing fall warblers.
Herb Wilson teaches ornithology and other biology courses at Colby College and perches in South China. He welcomes reader comments and questions at: