Handbook of the Birds of the World, vol. 16: Tanagers to New World Blackbirds.—Josep del Hoyo, Andrew Elliott, and David Christie, Eds. 2011. Lynx Edicions, Barcelona, Spain. 894 pp. 81 color plates, >500 photographs, and 766 distribution maps. ISBN 9788496553781. Hardcover, $275.—It was with both sadness and joy that I received volume 16 of the Handbook of the Birds of the World. Sadness because I have so enjoyed reading every volume of the series, and with this one it is coming to an end—or not! (see below); joy because this volume details some of the most exquisitely, beautifully plumaged of all passerine bird families: the tanagers, cardinals, blackbirds, buntings, and New World sparrows. The vast impact that the 16 volumes of the Handbook of the Birds of the World have had on ornithology dawned on me recently when I read a scientific paper and noticed that the acronym “HBW” was used without a definition. These books have become so ingrained in our daily lives, as professional or amateur birders, that defining HBW simply was not needed. We should all commend and express our gratitude to the editors, who have striven for exceptional artistic quality and scientific rigor, and yet maintained a timely publication schedule.

Volume 16 follows the classic layout of HBW by starting with a highly informative and timely essay, which in this volume reviews the important subject of climate change and birds (written by Anders Pape Møller; 27 pp.). The main body of the book covers an astonishing 762 species, in part due to the inclusion of the species-rich families Thraupidae (tanagers: 283 species, 64 genera) and Emberizidae (buntings and New World sparrows: 326 species, 76 genera), as well as the Cardinalidae (cardinals and grosbeaks: 42 species, 11 genera) and Icteridae (New World blackbirds: 111 species, 31 genera).

The use of DNA sequences of diverse genetic loci has revolutionized our understanding of the systematic relationships among many different organisms, not least among members of these four families of birds. Given our growing knowledge of the systematics of these passerines, it was a little disappointing that the four families are presented in very traditional groupings of genera, when, for instance, it has been demonstrated that some 19 genera placed here in the Emberizidae are instead more closely related to the tanagers, including the Galápagos “finches” (Geospiza, Certhidea, Platyspiza, and Camarhynchus). Similarly, some genera that are placed with the tanagers in this volume have closer affinities to members of the Emberizidae (e.g., Chlorospingus) or the Cardinalidae (e.g., Piranga). As the consistently excellent introductory systematic sections of the volume highlight, the higher-level classification of this collectively diverse and species-rich assemblage of birds is likely to remain in flux, so we should perhaps not pay too much attention to the absolute numbers of species or genera presently assigned to each of these four families. Indeed, Barker et al. (2013) recently published a comprehensive higher-level phylogeny centered on the same four families, together with the Parulidae, and argue for the recognition of some 16 families!

The systematic treatment of species assemblages within each of the four recognized families in the present volume is impressively comprehensive, with the authors readily adopting newly proposed generic names. I expect that close inspection of the species accounts within each family will engender some rigorous debate, both within checklist committees and among those of us interested in maintaining and expanding our life lists. For instance, J. D. Rising splits the Sage Sparrow into two species (Artemisiospiza belli and A. nevadensis; this split has now been accepted by the AOU Checklist Committee; see the 54th Supplement in this issue of The Auk), and the Fox Sparrow (Passerella iliaca) into four species (P. iliaca, P. schistacea, P. megarhyncha, and P. unalaschcensis; at present not under consideration by the AOU Checklist Committee).

The state of taxonomic flux apparent in this volume is indicative of our expanding knowledge of bird systematics and of biogeography as a whole. It is thus both fitting and exciting that Lynx Edicions has decided to publish a 17th volume in 2013 that will include a detailed summary of the major taxonomic changes in birds since the publication of the first volume in 1992. This volume will also include a global index and detailed account of some 80– 85 new species described in the intervening 20 years, including the description of several new species in the volume itself.

Aside from the introductory systematic accounts for each of the four families covered in volume 16, the remaining text follows the highly successful layout adopted in previous volumes. This includes detailed summary information about morphology, ecology, behavior, and the conservation status of the members of each family, which makes for fascinating reading. The initial introductory overview of each family is then followed by detailed species accounts of each member of the family, together with an excellent color distribution range map that is easy to interpret. The accompanying 81 color plates are beautifully illustrated, with many of the more distinct subspecies depicted. As in the other volumes, a very useful reference section is provided containing the citations of all the original descriptions of the taxa covered, along with a comprehensive bibliography. Finally, accompanying the book is a laminated plastic reference card that functions as a superbly useful index to all the passerine bird families covered in the last nine volumes of the HBW series.

Volume 16 maintains the exceptionally high standards set by the preceding volumes in every way. The book is simply a must-have, and I expect that for many bird enthusiasts this volume will complete their collection of the most comprehensive and beautifully illustrated series of bird reference books ever published. I have no doubt that this volume and the HBW series as a whole will prove a fundamentally important reference for many years to come, always providing a fascinating read, together with a great sense of pleasure when you come back to it time and time again.