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Racial identification and assessment in Britain: a report from the RIACT subcommittee Chris Kehoe, on behalf of BBRC Male ‘Black-headed Wagtail’ Motacilla flava feldegg. Dan Powell hroughout the past 100 years or so, mous in this paper), of a single, wide-ranging interest in the racial identification of bird species. The ground-breaking Handbook of Tspecies has blown hot and cold. Many of British Birds (Witherby et al. 1938–41) was the today’s familiar species were first described first popular work that attempted a detailed during the nineteenth century and, as interest treatment of racial variation within the species in new forms grew, many collectors became it covered and promoted a positive approach to increasingly eager to describe and name new the identification of many races. However, as species. Inevitably, many ‘species’ were the emphasis on collecting specimens was described based on minor variations among the replaced by the development of field identifica- specimens collected. As attitudes towards what tion skills, interest in the racial identification of constituted a species changed, many of these species waned. newly described species were subsequently Since the 1970s, and particularly in the last amalgamated as subspecies, or races (the terms ten years, improvements in the quality and ‘subspecies’ and ‘race’ are treated as synony- portability of optics, photographic equipment © British Birds 99 • December 2006 • 619–645 619 Racial identification and assessment in Britain and sound-recording equipment have enabled selection of others suspected of occurring but birders to record much more detail about the not yet confirmed. Any races not listed here are appearance of birds in the field, and this has either deemed too common to be assessed at been an important factor in a major resurgence national level, or would represent a ‘first’ for of interest in racial identification. At the same Britain. Appendix 1 lists several races that, time, new techniques and approaches in tax- although recorded only rarely, are assumed to onomy and systematics have promoted many be too regular to warrant the label of rarity; in forms previously thought of as races to full most cases, they are just too subtle to be species, which has created additional interest detected and therefore presumably go unno- from birdwatchers. ticed. A current list of accepted species and This article discusses BBRC’s approach to races on the British List up to 1st April 2006 can the recording and assessment of rare races of be found in Dudley et al. (2006) or online at species that would otherwise not fall within the http://www.blackwell-synergy.com/doi/full/ Committee’s remit. Some of these races (for 10.1111/j.1474-919X.2006.00603.x example ‘Siberian Stonechat’ Saxicola torquatus As intimated above, BBRC is also interested maurus) have traditionally been assessed as rar- in the races of a number of rarities that may be ities, but a complete list of the races that qualify diagnosable in the field. as national rarities has not previously been published. We hope that this document will clarify Diagnosability what has sometimes been a rather grey area, By their very nature, races tend to be subtle and also that it will explain some recently pub- entities, but the degree of subtlety varies. At one lished decisions relating to certain forms. extreme are distinctive races that seem to be as easily recognised as many full species (and in What is RIACT? some cases these may ultimately be elevated to Many extralimital races of common species species level). At the other extreme are races have already occurred in Britain, and doubtless that seem to be so poorly defined that it is ques- more will be discovered over time. Further- tionable whether their status is justified, let more, some taxa currently treated as races alone whether their identity might be reliably might eventually be promoted to species status, confirmed if they were to occur out of range. and this in particular prompted BBRC to set up Moreover, some individuals of a particular race RIACT (Race Identification Amongst Changing may be readily diagnosed while other individ- Taxonomy) in 1999, a subcommittee with the uals may be effectively indistinguishable from aim of establishing criteria for the identification other races. It is often the case that we simply and assessment of races. Initially, work focused do not know how, or even whether it is possible, primarily on rare species already being consid- to diagnose individuals of a particular race ered by BBRC, such as the races of Black-eared accurately in a vagrant context. Factors such as Wheatear Oenanthe hispanica and Isabelline individual variation, intergrades and aberrant Shrike Lanius isabellinus. Some of the work forms have not yet been fully researched in undertaken on these forms has already been many cases. published in BBRC annual reports, and it is Diagnosability is the key issue when it comes intended that more will follow. RIACT’s work to recording rare races; more specifically, the has now expanded to review those races of degree of confidence with which an individual commoner British species which are considered showing features suggestive of a particular race to be rare in a British context, or those which can be identified as being of that race is crucial. may be elevated to species status by the Historically, BBRC reported records of rare BOURC’s Taxonomic Sub-committee, and this races as ‘showing characters of’ the race in ques- paper stems from that research. tion. Implicit within that statement is a caveat that although the individual showed all or most Scope of the characters of the race in question, and no It is not the intention to review all of the rare contrary indications, there was still an element races that could potentially occur in Britain. of doubt as to whether it truly originated from Those discussed below include all those that the geographical area of the race in question. have previously been recorded in Britain (and The degree to which such a caveat was required are included on the British List), and a wide varied. Although we do not propose to continue 620 British Birds 99 • December 2006 • 619–645 Racial identification and assessment in Britain using this caveat for individual races, we will such submissions may ultimately be accepted as use it as a holding category for some difficult the form in question, in others they may rein- ‘groups’ where individuals cannot currently be force the need to take a cautious approach. assigned to an individual race with confidence Observers will be kept informed of any progress (e.g. ‘Eastern Lesser Whitethroats’ Sylvia made on particular issues, and we recognise curruca). that dialogue with observers is in itself a valu- When considering racial identification, the able tool as we try to establish whether certain ‘Geographical Variation’ section in BWP makes forms can be effectively identified and recorded. essential reading. Many identification papers Of course, work on the development of cri- and species or family monographs provide teria for judging claims should not be left to further guidance. For passerines, Svensson BBRC alone, and we encourage observers to (1992) provides an unparalleled guide to Euro- help us in clarifying diagnosability issues; we pean passerine identification in the hand and much prefer to receive submissions where the for many species presents in-depth treatment of observers have presented a well-researched case racial identification, although it is interesting to to support their conclusions. note how the treatment of certain forms differs from that found in, for example, BWP. In this The evidence required – field notes, report, we have listed (in parentheses at the end photographs, sound recordings, biometrics, of the text for each species group) some of the ringing recoveries and tangible proof of origins key references available for many of the races For many of the races listed here, details are discussed. given of the type of evidence required to A word of caution about descriptions in the support claims. To save endless repetition, it can literature is that when describing differences be assumed that one or more of the three basic between races, there is a (perfectly understand- types of evidence (a detailed field description, able) tendency for authors to concentrate on good photographs and a sound recording) is a those characters that typify, or enable separa- minimum requirement in most cases. The value tion of, different populations. They rarely touch of examining birds in the hand will be apparent on the extent of variation, or the degree of from the stated requirements for biometrics in overlap with other races, which are key consid- several of the following accounts – although erations when examining a potentially extralim- even for species where biometrics are useful in ital vagrant. The degree of individual variation helping to separate races, some or even many and the extent to which this, or intergrades individuals may fall into a zone of overlap. between adjacent races, may produce something Claims of a rare race which originate from a that could masquerade as a vagrant must always trapped bird should be accompanied by full be a consideration. BBRC will continue the biometrics, similar to those required for a approach, already in place for some races, of national rarity, ideally checked by another com- accepting only ‘classic’ individuals (e.g. of petent ringer and accompanied by in-hand ‘American Herring Gull’ Larus argentatus smith- photographs. If any body feathers are dislodged sonianus). We freely acknowledge that in con- during the ringing process, these should be pre- tinuing with this policy, some valid records may served in case molecular analysis is possible or be found not proven, but we feel that we can relevant.

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