HBW and Birdlife International Illustrated Checklist of the Birds of the World (2-Volume Set)

The Illustrated Checklist of the Birds of the World is breathtaking in scope and ambition. To have all of the world’s birds illustrated in a single collection of two volumes is a major milestone in the history of ornithology. This production by Lynx Edicions has taken 25 years since the first of the 17 volumes of the Handbook of the Birds of the World (HBW) appeared. HBW is a massive accomplishment and I would refer readers to the account in Wikipedia for a commentary on this. The advertisement on the end pages of volume 1 of the Illustrated Checklist advertising the 17-volume HBW series notes that HBW involved 277 authors from 40 countries, 33 artists, 1,151 wildlife photographers and around 100,000 bibliographic references. But for me the statistic that tells of the grand scale of this project is that 73 people were involved in editing and administration. To own any volume of the HBW series is to own a piece of ornithological history.

The Illustrated Checklist draws upon the specially commissioned illustrations for the HBW series. However, it is not merely a compilation of the plates of the HBW. The arrangement of species has been updated and reflects current thinking by the authors on what species are ‘splits’ or ‘lumps’. It distils the essence of literally thousands of scientific papers to place birds in a taxonomic arrangement that reflects their evolutionary relationships using available data and expert judgement. In preparing the illustrated checklist, further revisions have been made to take into account papers published since the publication of the corresponding volume of HBW. Therefore, this represents an updated publication in its own right.

Volume 1 on Non-passerines lists 1,982 papers. Volume 2 on passerines lists 2,740 papers, a total of 4,722 papers. This is not a simple bibliography of bird-related papers. The majority of these nearly 5,000 papers are cross-referenced in the facing text. This makes the two volumes a compact and formidable working tool, given how easy it is now to search and download a paper from the internet once a pointer has been provided to a key reference.

The illustrations are of the highest possible standard and complement the scientific rigour of the text. 28 and 14 artists are acknowledged in volumes 1 and 2 respectively. In the Illustrated Checklist, each plate has a distribution map and the facing text page has taxonomic notes and notes on the subspecies and distributions. The focus of the notes is to do with ascertaining whether a bird is a species or subspecies and their distributions and not on field identification. The inclusion of the maps on the plates as done in HBW is very useful when looking at a bird and seeing where it is found without having to flick one’s eyes across to the facing page which traditionally held the text and distribution map. Utility comes at a cost and this does mean that the stunningly beautiful plates have their aesthetic impact lessened.

Given its scope as an illustrated checklist, it does not attempt to be an identification guide. However, given its focus on taxonomy, there are many references and clues as to how similar species differ when decisions have been taken to split them. Furthermore, distinct subspecies are illustrated showing their distribution.

Volume 1 (Non-passerines) begins with a long introduction spanning over 30 pages (pages 19 – 54) explaining the problems with determining species rank. This section is necessarily technical with a discussion of the biological species concept and the phylogenetic species concept and their pros and cons. The introduction brings together very well, the technical issues in determining species and the interplay of morphological and genetic analyses. The authors have exercised judgement using the Tobias criteria to determine which species are to be split or not. The introduction contains a detailed discussion with figure 15 occupying a full page explaining the criteria in a visual presentation. In essence, the Tobias criteria attempt to introduce a quantitative assessment to remove some of the subjectivity in assessing species rank. However, as many authors have pointed out, all ranks whether species or families, are essentially a human construct. The Tobias Criteria comprise 5 taxonomic characters. These are; 1. Biometrics, 2. Acoustics, 3. Plumage and bare parts, 4. Ecology and behaviour and 5. Geographical relationship. The Tobias criteria employ these factors into a scoring system and its performance in determining species has corresponded well with work on genetics. The type of discussion in the introduction is typically outside the scope of field guides. I suspect the well thought out and illustrated introduction will bring these topics to a wider audience of field birders.

The end matter in Volume 1 Non-passerines contains two appendices on birds that have become extinct since 1500; the first with illustrations and the second without. 49 species are not illustrated because of the lack of a complete specimen or a reliable illustration. The third appendix from pages 776 to 811 contains maps of the world and looks like a mini atlas, with the opening double page serving as an index to the more detailed maps. This is a very helpful addition, given the number of birds which are endemic to a single island or a cluster of islands. I am accustomed to using google maps when reading natural history books. But when looking at some of the bird distributions in the Caribbean or the Indonesian islands for example, being able to turn to a large format page does make the process of reference much easier.

Volume 2 on the non-passerines has a useful pictorial index to the bird families in the endpapers for volumes 1 and 2 in the front and back endpapers respectively. The front sections are brief, reiterating the methodology used for delimiting species and a discussion on how the Tobias criteria fit with genetic analyses. HBW recognised 9,972 species of birds and the Illustrated Checklist sees the number increase by 992 species (or 11%) to 10,964 species: half of these arising from the work of other authors and half arising from the work of the authors of the Illustrated Checklist. This becomes yet another reason why the two volumes need to be treated as a new publication in their own right and not a simple, concise compilation of HBW.

Being able to browse a family of birds visually, to gain a visual impression of how similar a species is to other related species, and to see where in the world a species occurs, or where a genus or entire family occurs, is something that would take much longer to read and assimilate in a text-only checklist. Every time I open this book I am in awe of and admiration for the perseverance and drive that del Hoyo and his team have put in over the years to produce HBW and the Illustrated Checklist.