Neotropical Birding 21, 2017, pp. 66-69

Neotropical Birding 21, 2017, pp. 66-69

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HBW and BirdLife International illustrated checklist of the birds of the world. Volume 2, passerines by Josep del Hoyo & Nigel Collar. Barcelona: Lynx Edicions. 1,013 pp, 12,629 illustrations, 6,649 maps. Hardback. ISBN 978- 84-96553-98-9. €225 (approx. $239/£191).

 “With this companion volume to del Hoyo & Collar (2014), the HBW–BirdLife International project to review and revise the taxonomy of the birds of the world reaches its first goal.” So starts the introduction to the second (and final) volume of what, in shorthand, is known as the ‘Illustrated checklist’. Two years ago, then Neotropical Birding editor Chris Sharpe reviewed the first volume in this magazine (Neotropical Birding 16: 68–69). Chris eulogised about the book, considering it “unique... original... captivating... astonishing...”. The second volume is reviewed by the current Neotropical Birding editor. The reviewer (and hand on the magazine’s helm) may have changed, but the adjectives applied to the Illustrated checklist  do not. Chris’s perspective on volume 1 and mine on volume 2 could be twins.

Make no mistake, then, this is (the concluding part of) an epic work. It would be impressive enough, within two books the size and weight of Handbook of birds of the world (HBW), to illustrate every single bird species in the world (plus numerous subspecies) and to depict them on double-page spreads with their taxonomy explained, and their distribution summarised and mapped. But to simultaneously overhaul the taxonomy of the world’s entire avifauna makes for a simply majestic undertaking. For their vision, their perseverance and their delivery, the authors plus their five-strong team (which includes Cotinga editor Guy Kirwan), deserve both immense respect and heartfelt congratulations.

It is probably no secret to readers of this magazine that the HBW–BirdLife International approach to taxonomy has bemused many and irritated others (see, e.g., Remsen 2015, 2016; Collar et al. 2016). It broadly follows the Biological Species Concept, applying a tweaked version of the ‘Tobias criteria’, which scores each taxon against a range of characters. The goal has been to produce a standardised and more objective assessment of where species boundaries lie, fundamentally to rapidly inform conservation priority-setting.

Given the relative controversy of the HBW– BirdLife International system, it is unsurprising that the book’s introductory essay starts on the offensive, explaining that “a multiplicity of concerns and considerations... has driven the endeavour”. The authors caution, for example, against taxonomy on the basis of genetic analyses alone (citing the case of five “clear” species of seedeater Sporophila that “prove genetically inseparable”). Deeper into the polemic, however, the assertiveness is mottled with emollience.

Compared to volume 1, the authors make clearer overtures towards the benefits of DNA studies, which form “the single greatest driver of our use of the Tobias criteria”. The authors also more readily stress the integration of findings from other ornithologists. More than half the new species have been “generated by the work of others”. In the project’s six years, the authors have tracked and assessed at least 1,242 papers “on the taxonomy of passerines alone”—an incredible rate of one every two days. To my mind, they have done an admirable job of marrying their schematic with the breadth and depth of third-party information, conclusion and opinion. Neotropical Birding 21 67

The introduction is an erudite essay, full of precise but sometimes far-from-plain language (“reciprocally monophyletic mitochondrial lineages”, anyone?), that is presumably directed towards the highbrow end of the readership. Accordingly, I fear the opening words will wash over many purchasers. This feels like an opportunity missed to present (indeed justify), in layman’s terms, the chosen taxonomic approach to a wide market. Birders (as oppose to laboratory- or museum-based ornithologists) still yearn to understand what the HBW–BirdLife system is all about and why they might follow its taxonomy rather than, say, that of the International Ornithological Congress.

Some user-friendly touches to the introduction wouldn’t have gone amiss either. An explanation of the significance, in the species accounts, of coloured bullets and coloured highlights for English names of subspecies, say. Or an overview of taxonomic changes (splits, lumps and shuffles) by geographical region, comparing shifts in the Andes, say, with Indonesia. If space were an issue (unlikely in a 1,000-page tome, granted), the seemingly self-indulgent full page on ‘issues of nomenclature in the current volume’ could perhaps have been omitted. But don’t be deterred: do read the introduction, for it contains a horde of Neotropical nuggets. The authors alert readers to the splitting of Eastern Slaty Thrush Turdus subalaris from Andean T. nigriceps; the lumping of Hepatic Tanager Piranga hepatica; the importance of voice in separating Floodplain Thrush T. debilis and Campina Thrush T. arthuri from Black-billed Thrush T. ignobilis (for details of which see Neotropical Birding 19: 37); the occasional priority given to molecular evidence over the Tobias criteria (splitting Olivaceous Mourner Schiffornis olivacea from Northern Mourner S. veraepacis); and the importance of even spatial sampling before leaping to conclusions (meaning no full-species status for Venezuela’s Green-and-black Fruiteater Pipreola riefferii melanolaema).

Numerous species have moved families, with knock-on effects for scientific and English names. The introduction flags a few of these (amusing!) instances. Scarlet Tanager Piranga olivacea and Summer Tanager P. rubra prove to be cardinals, so should no longer really be called tanagers. Coalcrested Finch Charitospiza eucosma transpires to be a tanager (and so is renamed simply Coalcrest). The two ‘diuca-finches’ are also tanagers, but they also prove to be wholly unrelated so one or both needs a new common name! The introduction also offers some pointers towards potential future splits, as the authors found “previously unreported levels of distinctiveness” in voice between particular populations of Short-tailed Antthrush Chamaeza campanisoma, Common Miner Geositta cunicularia, Wedge-billed Woodcreeper Glyphorynchus spirurus, White-eyed Tody-Tyrant Hemitriccus zosterops, and Mountain Elaenia Elaenia frantzii—but not quite enough yet to bump up the taxa involved to full species.

Talking of which... the net result of the authors’ splitting and lumping is that their brave new world houses just shy of 10% more passerine species (6,592) than did the HBW series (6,008). Adding in the non-passerines from volume 1, this makes 10,964 species in total. As this is an illustrated checklist (which, as Chris Sharpe noted for volume 1, immediately sets the book apart from its competitors), the passerines have been treated to 642 new colour paintings (plus 1,208 that have been “improved”), making a phenomenal total of 12,629 artworks spread across 446 plates (almost half as many illustrations again as volume 1). Numerous subspecies are depicted, which is a boon to the birder as many are candidate splits: for example, there are paintings of more than half the 19 subspecies of Grass Wren Cistothorus platensis. All the images are excellent in quality, with oodles of ‘jizz’. Colours have been reproduced perfectly. The result is visually stunning.

Each species also has its own map (with the 57 extinct species, that makes 6,649 maps in total). Collectively, this cartography presents the most comprehensive, accurate and up-to-date assessment yet of the distribution of the world’s birds (indeed, say the authors, of “any complete class of animals”). The maps “have been checked, rechecked and checked again” to ensure their veracity. The HBW and BirdLife teams have done their work. It took me several hours of reading before I finally spotted an omission: Bolivian Earthcreeper Tarphonomus harterti has been documented in Argentina (López-Lanús 2008, Pearman & Areta 2016), so is no longer endemic to Bolivia. I spared myself the task of finding a second error.

The double-page spreads provide the fundament of the Illustrated checklist. This is a pair of books in which you can see, at a glance, what every single one of the world’s birds looks like, where they occur, how perilous (or not) their conservation status is (as of 2016 at least, as that year’s IUCN Red List update was produced handin- glove with the Illustrated checklist), and what their key taxonomic points are. For birders—quite aside from ornithologists and conservationists— the two volumes should thus be manna from heaven. Whether you read each page in taxonomic sequence or dip into the books randomly, you will deepen your understanding of the Neotropical avifauna, and probably prepare your avian bucket list or informally test your identification skills too. Although eyewateringly costly, the Illustrated checklist represents very good value for money. You will not regret the purchase.

James Lowen



Collar, N. J., Fishpool, L. D. C., del Hoyo, J., Pilgrim, J. D., Seddon, N., Spottiswoode, C. N. & Tobias, J. A. (2016) Towards a scoring system for species delimitation: a response to Remsen. J. Field Orn. 87: 104–110.

del Hoyo, J. & Collar, N. J. (2014) HBW and BirdLife International illustrated checklist of the birds of the world. Volume 1: non-passerines. Barcelona: Lynx Edicions.

López-Lanús, B. (2008) Bird sounds from southern South America/Sonidos de Aves del Cono Sur. Buenos Aires: Audiornis Producciones.

Pearman, M. & Areta, J. I. (2017) Species lists of birds for South American countries and territories: Argentina. Version 4 January 2017. Accessed from www. on 14 February 2017.

Remsen, J. V. (2015) Book reviews: HBW and BirdLife International illustrated checklist of the birds of the world. Volume 1: non-passerines. J. Field Orn. 86: 182–187.

Remsen, J. V. (2016) A “rapid assessment program” for assigning species rank? J. Field Orn. 87: 110–115.

Tobias, J. A., Seddon, N., Spottiswoode, C. N., Pilgrim, J. D., Fishpool, L. D. C. & Collar, N. J. (2010) Quantitative criteria for species delimitation. Ibis 152: 724–746.