British Birds » Editorials: BB eye: Getting your lists in order

Mark Holling By Mark Holling Imagine: you're planning a trip to eastern Europe in spring and you want to swat up on the distribution and ID criteria of Pied Ficedula hypoleuca and Collared Flycatchers F. albicollis. In the Collins Bird Guide they are, as you expected, after the warblers. Looking for a bit more detail, you find BWP is the same. But then, broadening the search, you turn to HBW; and their online option has bird families in a quite different order! After warblers, you find babblers, nuthatches and treecreepers, not flycatchers; they are immediately after thrushes, and before warblers in the sequence presented. OK, it's easy to find families quickly online. Not really a problem? But why the difference? Turning to BB for some reassurance, in the most recent BBRC report, Collared Flycatcher is in the middle of the thrushes and chats section. The BB List of Western Palearctic Birds confirms this. The Ficedula flycatchers are slotted in among various chats like Robin Erithacus rubecula and Common Nightingale Luscinia megarhynchos. Yet Spotted Flycatcher Muscicapa striata is after the thrushes but before Robin. Surveying a range of field guides and other books just adds to the variety – and the confusion. Many BB readers will recognise the issue, but perhaps not be too surprised about this, since they will have seen many changes in the sequence of bird species in the last decade or so. The three breeding bird atlases, each produced 20 years apart, show how much the sequence can change across even quite short timescales. Twelve years ago this month BB readers found that the comfortingly familiar 'Voous' order that had seemed almost set in stone for so long had changed. Now, the list began with wildfowl and gamebirds rather than divers and grebes (Brit. Birds 97: 2–5). That change followed the recommendations of the BOU Taxonomic Sub-committee. At the time this seemed all very disruptive but field guides and bird reports now largely follow this sequence and, arguably, we have got used to it. But that big change turned out to be just the beginning, with almost annual changes in the sequence of species within families and families within orders. In 2007, there was another big shuffle, this time in the sequence of families within Passeriformes. And in 2012, the falcons were no longer to be found after the other birds of prey but next to parrots at the very end of the non-passerine families. Madness?! Like many, my first bird book was the Observer's Book of Birds. As a newcomer to the hobby, I struggled to find birds in this book so was forever using the index. Back then I was unfamiliar with bird families and how they related to each other. That understanding came with time and experience. The introduction to the Observer's guide stated that there was 'now a trend internationally to adopt what is called the Wetmore order of classification' – a system adopted by the BOU in 1952. The main purpose was to 'place families which are presumed to be closely related near to one another and to place more primitive families near the beginning of the list with the more advanced near the end'. Thus began the long-established sequence beginning with divers and grebes and ending with buntings and sparrows, although a revision in 1977 by Karel Voous later became the standard and was used by BB. Perhaps we had been lulled into a false sense of security. From the late 1970s through to 2004 we had a largely static list; all the controversy was about what common names we should use, rather than in what sequence they should appear. But it is easy to forget that the list of British birds was by no means static beforehand. Pick up a bird book from the early twentieth century and you would see the crows and then other passerines at the beginning, with rails and gamebirds at the end. Although the sequence now in use would be almost unrecognisable to Dr Wetmore or Prof. Voous, the principles are still the same. Recent advances in genetic analysis have greatly changed our knowledge of what is primitive and what isn't. One of the implications of these frequent and disruptive changes is that publications become dated and birdwatchers, especially new ones, find it very confusing. It means that editors and compilers of lists have to decide whether to change every time or just ignore it all and freeze their lists at some point in the past. Another implication is that any numbering system based on the recommended sequence becomes useless once that sequence changes. Before the widespread use of computers for bird recording, this mattered less. The number was just a unique identifier for a particular species. The Euring system, developed in 1963 to organise and standardise European bird ringing, provided the first widespread standard numbering system and helped to ensure that files of species data could be stored in such a way to guarantee the correct sequence. But as taxonomic changes have come along, renumbering on a regular basis has become necessary and there is now no standard. I maintain that when you pick up a field guide or a county bird report, or browse one of the regular reports in BB, you should have a reasonable idea of where a species might be without the need to use an index. And you shouldn't need to know when the book or report was published in order to know where to look. The same principle applies to filling in a recording sheet for a survey such as WeBS or submitting records to a scheme such as BirdTrack. Of course, Ctrl-F is the obvious way to find anything in this digital age, but paper is not disappearing as fast as we might have thought. One solution sometimes put forward to resolve these issues is to forget the taxonomic arrangements and just sequence birds alphabetically. But this really wouldn't work. Would you find Common Pochard Aythya ferina under 'P' or 'C'? Or indeed 'A'. (Fan-tailed Warbler Cisticola juncidis or Zitting Cisticola, anyone?) Should we just accept that, in the spirit of Wetmore's guiding principles, there will be amendments to the taxonomic sequence each year, or in most years? I have an interest in current taxonomic thinking but I don't think we should. Perhaps the problem is the conflict between taxonomists using robust science to determine the best sequence (known so far) which produces new results ever more frequently, and the impact that has on the end users, many of whom are just birdwatchers reading scientific journals and bird reports. I wonder instead if some kind of moratorium on list-sequence changes could be instigated. New species could be added to lists, of course, but the order in which they appeared would remain static for (say) a decade, and then all the recommenced sequence changes could be implemented at one time. The reason behind each change could still be published by the BOU annually as now. But books, bird reports, online lists and BB itself would not make any amendments until the agreed date. The BOU has been working towards establishing a unified European-wide taxonomic model but as this has proved impossible it decided that this aspiration would be better achieved by disbanding its own Taxonomic Sub-committee. Instead they will be reviewing the available global taxonomies with a view to adopting one system for all BOU activities, including the British List. Perhaps during this hiatus the European committees could also agree on a new but stable list for 2020–29? Most of what I have said relates to the taxonomic sequences of birds of the Western Palearctic used in British and some European publications. But across the world there are four main taxonomies adopted by other organisations and in different countries: Clements, HBW Alive/BirdLife International, Howard and Moore and the International Ornithological Congress; the IOC list is the one currently used by BOU and hence BB. It is too much to ask that all of these might remain static for ten years at a time too? Perhaps by 2020 there could be one global sequence which will last for a whole decade! The post BB eye: Getting your lists in order appeared first on British Birds.