Although predominantly dealing with subspecies, this section of the website also includes some information on rare full species e.g. Cackling Goose, Siberian Stonechat and Italian Sparrow.
Traditionally, BBRC considered records of rare subspecies only where they were well-defined and easily identifiable in the field. With improving knowledge of their identification characters and with digital photography and sound recording equipment giving a greater ability to document records, it is clear that rare subspecies will feature ever more in BBRC’s remit. Furthermore, shifting taxonomy is already elevating some former subspecies to the level of full species and this trend seems likely to continue. In this context it is clear that BBRC needs to continually develop its policy on which taxa are considered, what evidence is required in submissions etc. A major step in addressing this issue was taken with the publication of Kehoe (2006). This paper can be downloaded from this site (under Annual Reports & Papers). However, it has been clear for some time that a full overhaul of the 2006 paper was required. This section of the BBRC website therefore updates and expands on that paper, setting out the latest position on subspecies considered to be rare in a British context. The list of rare subspecies dealt with here is not intended to be exhaustive but this section covers all those which have already occurred in Britain as well as those considered to have the potential to do so. The new accounts will assist the Committee with assessing claims of rare subspecies currently in the system and also inform consideration of future claims. Each follows a standard format:
Taxonomy – a description of the current taxonomy, highlighting any debated aspects (e.g. differing treatments, potentially invalid subspecies, proposals for elevation to full species etc.).
Status – a list of the subspecies on the British List, with a brief summary of their status, followed by any subspecies suspected or assumed to occur and any which might have the potential to do so in future.
Identification – brief comments on the problems/issues involved.
Evidence – the proposed indicative evidence requirements to support any submission.
The accounts are fully referenced and carry a date on which when they were last updated. They will be updated regularly, to reflect the inevitable continuing developments in taxonomy as well as our evolving knowledge of status and identification. All significant updates will be advertised on the Twitter feed @_BBRC and major revisions will also be featured in British Birds.
BBRC has previously adopted the concept of ‘informal submissions’ for rare subspecies, an encouragement to observers to submit claims but also an acknowledgement that the taxonomic and identification issues can be complex and that further research might be required. The Committee has also adopted a policy of not publishing any such claims as ‘not proven’. However, as well as facilitating a number of acceptances, this approach has led, perhaps inevitably, to a considerable volume of records that have simply stalled. Some of these are highly promising but just fail to meet the threshold for acceptance while others are not adequately documented or considered not to relate to the subspecies claimed but, under the current policy, cannot be published as ‘not proven’. This is not a satisfactory situation.
BBRC Annual Reports now therefore contain an additional Appendix, entitled ‘Records held until taxonomy or identification criteria are resolved’. This lists those claims of rare subspecies (and also full species) which look highly promising but which, through no fault of the observer(s), cannot be progressed on current knowledge. This Appendix is intended to provide greater visibility for such claims and also to facilitate revisiting any claim in the light of new knowledge. Observers’ names are not published.
With respect to rare subspecies, this Appendix relates largely to those where the taxonomy is not settled and/or no robust field identification criteria (yet) exist. In many of these cases, identification may ultimately depend on evidence such as biometrics, a ringing recovery or DNA evidence but in some cases ongoing research may result in the definition of field characters too. This Appendix is particularly relevant for claims of ‘firsts’, where the acceptance threshold is inevitably higher.
To warrant a listing in the Appendix, the evidence supplied must be comprehensive, fully indicative of the claimed identification and contain nothing to suggest otherwise. Claims which are not adequately documented or considered not to relate to the subspecies claimed are published as ‘not proven’.
A full overview of BBRC’s approach to rare subspecies can be found in the January 2016 issue of British Birds (Stoddart 2016).
Kehoe, C. 2006. Racial identification and assessment in Britain. Brit. Birds 99: 619-645.
Stoddart, A. 2016. Rare subspecies in Britain. Brit. Birds TBA (in prep.).