Most readers of British Birds will have a reasonable knowledge of the role of the British Birds Rarities Committee (BBRC) in assessing sightings of rare birds (not least thanks to the BBRC’s annual report, such as the one published in this issue) and the role of the British Ornithologists’ Union Records Committee (BOURC) in maintaining the British List. Nonetheless, the two-committee system that exists in Britain is rather unusual and means that the first record of any new species or subspecies for the country is adjudicated by two sets of voting members: first, by BBRC, and then by BOURC, whose functions complement and support each other. This two-tier procedure results in a thorough assessment process through which both the identification and the origin of the bird are established, these two issues being critical for the integrity of the British List.
Here, we describe the history of BBRC and BOURC, and the processes by which the two committees assess and judge records, allowing BOURC to manage and maintain the British List.
The role of BBRC
British Birds was established in 1907 and the publication has formed a link between birders and more academic ornithologists ever since. During the first 50 years or so, reports of rare birds in Britain were submitted to the editors, who published them in BB if they were deemed acceptable, often with descriptions and associated notes. By the mid 1950s, this situation had become undesirable and increasingly untenable, with an ever-increasing number of records of rare birds to deal with and a growing demand on space within BB, plus a realisation that some species once considered rare were occurring in Britain with some regularity. The editors of BB decided that an annual report, detailing all rare birds from the past year, was the way forward, containing just enough detail to form a historical archive but not too much as to fill more than one issue. A list was agreed upon for species that would constitute rarities and a committee of ten of the leading ornithologists of the time – the Rarity Records Committee – was formed, with the remit of collating and assessing all of the 400 or so annual observations of these rarities.
The BOU’s British Records Committee (later the BOURC) had been maintaining and managing the official British List since it published the first List of British Birds in 1883. A link between the Rarity Records Committee and the British Records Committee was established from the start, both in principle and in practice, no doubt helped by the fact that H. G. Alexander, who sat on the new Rarity Records Committee, was then Chair of the British Records Committee. It seems clear from the outset that this new Rarity Records Committee would act as the initial arbitrators on new species for the British List, and all accepted records of species new to Britain (and, indeed, the Republic of Ireland, which was included up to 2001) would then be passed on to BOURC for them to assess independently and formally admit to the British List. It was stated that BB would not publish any records of potential firsts for Britain before they were accepted by BOURC. This acknowledged legitimacy of both Committees for each other has been a constant strength over the last six decades, and the close working relationship continues to this day, with the BBRC Chair having an ex-officio seat on BOURC.
From its inception, BBRC has worked closely with the county recording network. Ideally, observers submit their rarity records to the relevant county recorder, and the record(s) are then passed on to BBRC. This way, counties can easily maintain a watching brief on what is and is not in the system. Some counties, such as Yorkshire, circulate national rarities around the county committee before they go to BBRC, and this can flush out pertinent aspects of some submissions, as well as giving county committee members experience of dealing with national rarities.
The process of rarity submission and publication has changed little during the life of BBRC. Some may see this negatively, but there are many reasons why it should be seen as a strength. Indeed, the model has successfully been replicated and repeated many times around the world. There are certainly places where this model is not ideal, mainly in the case of small birding communities with few rarities to assess, and a wider discussion on this would make a good subject for a future BB eye.
Once submitted, the record is given a reference number that will remain with it for ever, and the submission is loaded into BBRC’s private database. Committee members vote on each record as OK, Not Proven (NP) or Pend. Most records receive an OK vote, and this is straightforward: for species already on the British List, the record is accepted and will appear in the next annual report.
If a record receives three or more NP votes on its first circulation, then this is final, and the record is not accepted. However, one or two NP votes result in a recirculation of the record and, in these scenarios, it is usually the case that a discussion takes place amongst voting members and the outcome is usually resolved fairly rapidly. If there are no or just one NP vote after recirculation, the record is accepted. By allowing space for this one NP vote, one voting member cannot single-handedly block a record from acceptance, but they do have the opportunity to make their case to the rest of the Committee.
The option to Pend is a rather infrequent outcome, and there must be a clear reason for the pend vote, rather than simply swerving a difficult record! Waiting for an in-press identification paper or the results of an ongoing review would be good reasons, as would waiting for local or external input on a record, such as on sound recordings or from recognised experts on a given species.
In the case of votes on putative firsts for Britain, there are clear criteria that should be fulfilled for any submission. These are laid out in Appendix III of our constitution (www.bbrc.org.uk/about/constitution) but, as a general rule, place a much higher degree of duty on the observer to not only prove the identification but also prove the occurrence itself. Once the Committee is happy with the record and all members have had a chance to vote and comment, the entire file is passed on to BOURC for them to adjudicate both the identification and the provenance.
The role of BOURC
On arriving with BOURC, the file is assessed by the Committee to ensure that BOURC agrees with BBRC’s decision on the identification of the bird. In the extremely rare cases where BOURC disagrees, the record is returned to BBRC for further consideration. Usually, however, BOURC agrees with BBRC’s identification and the Committee’s primary focus turns to provenance – essentially, establishing whether the bird in question is of wild origin. Sometimes this is straightforward, such as when a species is strongly migratory, moving large distances, rare in captivity and has already been observed as a vagrant outside its natural range. In other cases, however, determining whether a bird has arrived in Britain naturally can be much more problematic.
In cases where the vagrancy potential of a species is unclear, a significant component of BOURC’s work is to evaluate and determine this. A recent example was an observation of a Paddyfield Pipit Anthus rufulus. Despite some historical accounts suggesting that the species was migratory, exhaustive analysis of museum specimens and a reappraisal of the published literature established that this was not the case, with earlier literature being incorrect and the species being highly resident. This review of evidence played an important part in the decision to accept Paddyfield Pipit to Category D, which does not form part of the British List (see below) (Lees et al. 2022).
Other recent challenging species considered include Dalmatian Pelican Pelecanus crispus, Western Swamphen Porphyrio porphyrio, Chinese Pond Heron Ardeola bacchus, Bearded Vulture Gypaetus barbatus and Mugimaki Flycatcher Ficedula mugimaki. The first three species were admitted to Category A of the British List, while the last two were not (McInerny & Stoddart 2017, 2018, 2019; McInerny 2019). In all cases, a detailed and thorough analysis of the species’ population size, movements, vagrancy potential and captive status allowed these decisions to be made.
Judgement is further complicated when species are widely kept in captivity in Britain and Europe, with regular known escapes in the wild. The range of species kept (legally and illegally) is vast, with even seemingly unlikely taxa such as swifts being found in the captive bird trade! This means that BOURC has the challenge of ascertaining – sometimes amongst a number of records of a given species – whether any birds can be confidently assigned to wild origins amongst the many that are judged to be escapes. This problem is especially prevalent with wildfowl, and BOURC has developed and published criteria by which wild ducks and geese can be distinguished from escaped birds, involving careful consideration of migration patterns and potential carrier species, amongst other factors (Stoddart & McInerny 2020). The process has recently been used to reassess Falcated Duck Mareca falcata and Ross’s Goose Anser rossii, resulting in both species being admitted to the British List (Batty & McInerny in prep.).
Over time, BOURC’s structure and processes have evolved to develop a set of procedures and principles to use when considering each new species or subspecies for admission to the British List. These procedures have been described in BOURC reports so that the processes are transparent. Crucially, the procedures ensure that the Committee judges and assesses records in a consistent manner so that decisions to admit a new species or subspecies to the List are robust and defendable.
BOURC occasionally re-reviews species that were previously not admitted to the British List, but this process is strictly managed. Files cannot be reopened ad hoc but rather only under two circumstances: firstly, if new evidence is presented (this might be in the form of a subsequent pattern of records in Britain or Europe, for example); or, secondly, in the case of species assigned to Category D, where files are reviewed every five years as a matter of protocol. Both Ross’s Goose and Falcated Duck were recently admitted to the List following such Category D reviews, while a reassessment of Mugimaki Flycatcher (also in Category D) resulted in its continued omission from the British List. The last record has now been reviewed on several occasions, and by several different memberships of BOURC, with all reviews concluding that the escape likelihood of the individual bird in question at the time of its occurrence was too great, despite the species being a predicted vagrant (McInerny & Stoddart 2017).
The first List of British Birds (BOU 1883) contained 376 species, and the 2nd edition (BOU 1915) contained 423 species. Since 1956, BOURC has issued reports and updates to the List in the journal Ibis (BOU 1956), with the most recent being the 54th BOURC Report published in July 2022 (BOU 2022a). Since the 7th edition, the British List itself has also been published in Ibis, with the 10th edition, listing 628 species, also published in July 2022 (BOU 2022b). All BOURC Reports and the four most recent editions of the British List are open-access and free to view online (https://bou.org.uk/the-british-list)
Although it’s reasonably well known that BOURC assesses records of modern-day firsts for Britain, a little-known function of the Committee is to identify first records of all bird species on the British List. As many of these are historical and pre-date the start of formal record keeping by BBRC and BOURC (1958 and 1883, respectively), BOURC has developed and published criteria to specifically judge such historical records, which are different from those used for contemporary first records. In particular, the issue of fraud, which was historically prevalent among collectors, needs to be considered (BOU 2018).
Finally, another important function of BOURC is the management of the categories that define the British List. Six categories determine which species are on the List (species assigned to Categories A, B and C), and those species which are not on the List (species assigned to Categories D, E and F) (BOU 2022b). The definitions of these categories are continually reviewed, with the most recent developments being the refinement of Category C, which took account of birds from translocated and self-sustaining populations (McInerny et al. 2022), and the first formal publication of species assigned to Category F, the ancient birds of Britain (Cooper et al. 2022). The Category C review was completed in collaboration with the Association of European Records Committees (AERC), and will be implemented across Europe – an important international collaboration, which will allow for the consistent treatment of individuals from translocated and self-sustaining populations by all European rarities committees.
Chris McInerny would like to thank Steve Dudley (BOU Chief Operations Officer) and James Gilroy (BOURC Chairman) for comments on the BOURC text, and past and present members of BOURC for their contributions to committee work over the years. BOURC also acknowledges the important dialogue and collaboration with both BBRC and AERC to complete its work.
Batty, C., & McInerny, C. J., on behalf of BOURC. In prep. The Ross’s Goose in Britain. Brit. Birds.
British Ornithologists Union (BOU). 1883. A List of British Birds Compiled by a Committee of the British Ornithologists’ Union. John van Voorst, London.
— 1915. A List of British Birds (Second and Revised Edition). BOU, London.
— 1956. British Ornithologists’ Union British records sub-committee: first report. Ibis 98: 154–157.
— 2018. British Ornithologists’ Union Records Committee (BOURC): 49th Report (October 2018). Ibis 160: 241–248.
— 2022a. British Ornithologists’ Union Records Committee (BOURC): 54th Report (July 2022). Ibis 164: 929–931.
— 2022b. The British List: a checklist of birds of Britain (10th edition). Ibis 164: 860–910.
Cooper, J. H., Stewart, J. R., & Serjeantson, D. 2022. The birds of ancient Britain: first recommendations for Category F of the British List. Ibis 164: 911–923.
Lees, A. C., Batty, C., & McInerny, C. J., on behalf of BOURC. 2022. The Paddyfield Pipit in Britain. Brit. Birds 115: 250–260.
McInerny, C. J., on behalf of BOURC. 2019. The Dalmatian Pelican in Britain. Brit. Birds 112: 403–406.
—, & Stoddart, A., on behalf of BOURC. 2017. Recent BOURC decisions: Mugimaki Flycatcher and Chinese Pond Heron. Brit. Birds 110: 345–354.
—, & —, on behalf of BOURC and BBRC. 2018. The ‘Purple Swamphen’ in Britain. Brit. Birds 111: 515–518.
—, & —, on behalf of BOURC and BBRC. 2019. Bearded Vultures in north-west Europe. Brit. Birds 112: 26–34.
—, Crochet, P-A., & Dudley, S. P., on behalf of BOURC and AERC. 2022. Assessing vagrants from translocated populations and defining self-sustaining populations of non-native, naturalized and translocated avian species. Ibis 164: 924–928.
Stoddart, A., & McInerny C. J., on behalf of BOURC and BBRC. 2020. The Falcated Duck in Britain. Brit. Birds 113: 46–53.
BOURC papers referenced above are free to access and can be found at https://bou.org.uk/british-list/bourc-reports-and-papers/
Paul French, BBRC Chair, 1 Greenfield Bungalows, Easington, East Yorkshire HU12 0TZ; e-mail [email protected]
Christopher J. McInerny, BOURC Secretary, School of Life Sciences, University of Glasgow, Glasgow G12 8QQ; e-mail [email protected]
Paul French is a Senior Ornithologist at HiDef Aerial Surveying and Chair of BBRC. Chris McInerny is a Reader at the University of Glasgow, Secretary to both BOURC and the Scottish Birds Records Committee, and works on a wide range of natural history, but particularly birds and reptiles in Scotland.