The following critiques express the opinions of the individual evaluators regarding the strengths, weaknesses, and value of the books they review. As such, the appraisals are subjective assessments and do not necessarily reflect the opinions of the editors or any official policy of the American Ornithologists' Union.
This is a careful, useful, and important work on measuring birds and a very welcome addition to the ornithological literature. It is a spiralbound, octavo-sized book on water-resistant paper with sturdy covers, made for ready use in the field, in the museum collection, or in specimen preparation. It is printed in landscape format in parallel columns in English and German and is well written and well illustrated. The authors correctly note that this is the first comprehensive work on the subject since the classic by Baldwin et al. (1931). This volume is more comprehensive, however, because the authors integrate measurements taken in bird banding and some of those used in specialized studies of morphology. The many types of measurements possible for ecomorphological studies are not all included; only those deemed to have become standards since the 1970s are incorporated. The goal is to guide users and hopefully achieve “a standardised coding and documentation of the measurements used” (p. 11). The authors certainly succeed in providing users an excellent guide.
This volume was written by a team of authors (S. Eck, J. Fiebig, W. Fiedler, I. Heynen, B. Nicolai, T. Töpfer, R. van den Elzen, R. Winkler, and F. Woog) who make up a group dedicated to “Ornithological Collections” in the German Ornithologists' Society (DO-G). The book is divided into nine chapters focused on aspects of measurement and two additional chapters that provide references and an index. The topics include why we measure birds; measurement accuracy; comparison of measurements between fresh or living birds and museum specimens; numbering flight feathers; live bird measurements; skull ossification as an aging method; body mass; measuring equipment; and detailed drawings and verbal descriptions of specific bird measurements. Overall, I found it an informative and rather comprehensive work, and I enjoyed reading it.
The section on measurement accuracy and reliability is right on. Not only are within-observer variations important (for example, I try not to measure >50 museum specimens in a day to minimize error), but instrument quality and considerations of precision versus accuracy are critical. There is a good chapter on shrinkage that correctly concludes that there is no universal correction factor possible, given the variability of changes documented between live or freshly dead birds and the same individuals measured later as dried museum specimens.
As a measurement nerd, I thought that I might find a number of areas of disagreement, but these were relatively few. The authors sidestep one area of potential contention, that of measuring wing chord versus flattened wing length, by focusing mostly on the latter, which is the use that prevails across Europe. The amount of training that seems to be required among observers to attain accuracies to just 1 mm (pp. 33–34) does not argue for the strength of using flattened wing lengths over chord, although both may be superceded by accuracies obtainable by measuring individual primary lengths (Jenni and Winkler 1989). Also, the fact that there are fully five wing-length measurements that are not wing chord suggests that the final word on the best way to measure wing length has yet to be written. Wing chord, which is the prevailing method of measuring wing length in museums and in the Americas, does not appear in the index.
Although mentioned in more than one place, mostly with respect to among-observer variation (e.g., pp. 33–38), repeatability analyses would have benefited from a focused discussion (e.g., Bailey and Byrnes 1990). Other quibbles are small. Preparators of scientific specimens are usually not called “taxidermists” in most English-speaking countries (that term being reserved for preparators of specimens for exhibit). The term “juvenile” is too vague (Erritzoe et al. 2007); hatch year—second year (HY—SY) is a better descriptor. The summary of skull ossification is too narrowly focused on temperate-zone birds; many tropical passerines can take much longer than temperate-zone species to become fully ossified. Three-dimensional measurements and reflectance spectrophotometry will require their own summaries elsewhere. Measurement abbreviations are suggested but might have been reconciled with some already in use (e.g., Winker 2000). Finally, it is suggested that some measurements require softening of museum skins, which as a curator I would not permit. But these are rather small issues among specialists who are equally passionate about how best to measure these animals that we study so intensively.
The illustrations are excellent, making this book immediately accessible to the newcomer. The only caution I would give the novice is to also consult the literature to determine which measurements out of this universe of the possible are likely to be the best to take for a particular study. But even those of us who are old hands at measuring birds can benefit by exploring this universe to see whether new, alternate, or better methods can be applied. Everyone who measures birds would do well to study this volume.