Ornis Fennica 92:153–156. 2015

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The clash of checklists

Josep del Hoyo & Nigel Collar: HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. — Lynx Edicions 2014.904 pp. ISBN 978-84-96553-94-1.

Ornithologists have many options for a taxonomic checklist of the world’s birds. There are currently three main works which are updated on a regular basis and thus provide a more or less similarly attractive and practical option: The Clements Checklist of the Birds of the World, The Howard and Moore Complete Checklist of the Birds of the World and the current title reviewed here. Furthermore, the IOC World Bird List can actually be considered as the fourth main option. Originally it was not aimed as a taxonomic reference work but its purpose has been to provide vernacular English names for the world’s birds. However, it has imprecise become one, possibly because it is appealing for ornithologists and birdwatchers due to the frequent updates which quickly reflect the results of new research and discoveries.

All the above-mentioned pieces of work use a slightly different approach when it comes to species limits and systematic order of taxa. Apparently these differences have been so minor (or could there be more important reasons?) that none of them have emerged as a clear top choice for the ornithological community. The “Clements”, which now is maintained by the Cornell Lab of Ornithology, is highly popular in the New World and the “Howard and Moore” is traditionally widely accepted. Such a notable body as the International Ornithological Congress stands behind the “IOC checklist” and the Handbook of the Birds of the World (HBW) series team and BirdLife International now have their own stall at the market. This first volume of the HBW and BirdLife checklist was published in 2014, and it presents the non-passerines of the world. The second volume with passerines is expected to come out in 2016.

When the HBW and BirdLife checklist was published, my initial thought was why yet another checklist? In lieu of agreeing to any one authority, new ones are created and the ornithological community is “split”, instead of “lumped” regarding common system. Taxonomy is essentially a tool to define nature into concepts (i.e., taxa) which wean use to communicate with each other in matters of conservation, science, legislation and so on. With a new taxonomy to follow, ornithologists have once again a new “language” to communicate with. This hardly helps us understand each other better?

The above is of course a more universal remark for professional taxonomists, and it is really beyond the scope of this book review to get into the discussion on which of the above-mentioned checklists should be adopted. However, some thoughts should be expressed about the current title in this regard. The HBW and BirdLife checklists using, as it says in the book, a modern version of the Biological Species Concept. In this version, a scoring system described by Tobias al.(2010) has been adopted for discerning the gratitude of differences in morphology, vocalizations, ecology and geographical relationships separately. The scores of each feature are added up and the result is compared to the nearest believed relative along. The aim is to assess species limits on a more consistent and less subjective manner. The authors are not claiming this approach to be completely objective in all cases. A few scientific studies using this method have already been published, but seemingly it has not been adopted by the majority of researchers.

This modern method was applied to the birds listed in the HBW series, and as a result, 21 species were lumped and 462 species were split, giving atonal of 4,372 species in this first volume of non-passerines. Most splits concerned pigeons (46 splits), woodpeckers (39) and parrots (46). Compared to the other main checklists, the number of species is somewhat greater. This might be goodness in terms of conservation, because in many countries legislation does not necessarily concern subspecies.

To see how the Tobias criteria have worked in practise, I checked some recent taxonomic dilemmas mostly from the northern hemisphere. Green-winged Teal seems to be one of the lumps, as it is presented as a subspecies of Common Teal. Tropical, Persian and Bannerman’s Shearwaters have been split from Audubon’s, which now includes subspecies baroli and boydiin addition to the nominate lherminieri. Under the species name Arctic Herring Gull there are subspecies smithsonianus (the nominate), vegae and mongolicus, and Lesser Black-backed Gull now includes barabensis. There are quite a few mouth-watering cases in passerines, so I am looking forward to the second volume.

The book begins with a 35-page introduction, dealing with subjects like speciation and species concepts, species-level taxonomy including DNA studies, and a very detailed description of the new taxonomical approach chosen for the checklist –the Tobias criteria. Finally, the introduction thoroughly guides how to use the book. Introduction is followed by the main part – the checklist. Towards the end of the book, there are appendices presenting extinct species and 36 pages of large-format maps for geographical reference. Bibliography and index fill the last 90 pages.

The checklist, or the species accounts, base largely on the texts of the HBW series. Text size is among the smallest I have witnessed in an ornithological book, which makes reading challenging in non-optimal lighting conditions, but I understand that space was not plentiful when a book has 904 pages. For each species, the vernacular name in four languages and the scientific name are given, as well as a cross-reference to the volume and pages in the HBW series, and the global IUCN conservation status. The text is divided into two chapters: “Taxonomic notes” and “Subspecies and distribution”. The former is commonly the longer one, accounting for the many changes in taxonomy compared to previous works, giving details of genetic diversity or relationships within family or genus. It explains the reasoning behind changes in nomenclature and splitting or lumping of families, genera or species. It further lists the magnitude of differences in the various features along the Tobias criteria, whenever applicable. The latter chapter gives a detailed description of the distribution at a subspecies level. The most notable difference to any of the other checklists is that the HBW and BirdLife checklist is, as the title implies, illustrated. In other words there are more than 8,000 colour paintings of all the species and many subspecies featured in the checklist. The paintings have been reproduced from the HBW series, but there are quite a few new and improved paintings compared to the series. A scale is also included in the plates, allowing estimates of the real size of birds. In addition to the illustrations, each species come with a colour map of the species’ breeding, migratory, and wintering distribution, also from the HBW series (but updated).

The illustrations and the large maps make the book extremely user-friendly, and I’m sure this feature alone is enough for many people, especially for birdwatchers working on their world list, to decide for the advantage of this title. It is utmost convenient to skim through the list of birds and look at the maps and the images on the facing page, and compare plumage details and distributions of sister species. Actually, it is great to be able to get an idea of the looks and distribution of a whole genus, or even family, with one glimpse.

Almost 30 artists were involved in painting the illustrations, and although one can clearly see major differences in the styles of different artists, they are all excellent paintings. Author and artist contributions are fully listed in pages 16–17. In most cases the various subspecies and different plumages are presented, too. There are no flight images of raptors or paintings of juvenile stints to name a couple of examples, but then again this is not an identification guide. However, albatrosses and petrels as well as swifts are painted in flight only.

The HBW and BirdLife International Illustrated Checklist of the Birds of the World acts as yet another world bird checklist to choose from. It uses a new taxonomic approach, which, however, has not really received a wide acceptance within the scientific community. Nevertheless, the checklist itself is bound to become a very popular choice, being backed up by the BirdLife International, and as a matter of fact, it has been adopted by the United Nations Convention on the Conservation of Migratory Species of Wild Animals, and also by the European Commission to be used in their decision-making. The modern taxonomic approach also seemingly does have benefits when it comes to bird conservation. Further, because of the illustrations, this is the most handsome and lister-friendly checklist of them all. It is simply an amazing book and an undisputed titan of its kind.

William Velmala


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