The British Ornithologists’ Union (BOU), through its Records Committee (BOURC), has maintained and managed the British List since its inception, with the first List of British Birds published in 1883 containing 376 species, and the 2nd edition in 1915, with 423 species (BOU 1883, 1915).
The Committee comprises up to ten members with a broad range of interests and skills necessary for the maintenance of the British List (including identification, vagrancy, ringing, rare bird occurrences, working with specimens, captive birds) and works closely with the British Birds Rarities Committee (BBRC) on all contemporary first records considered for admission to the List (see Structure and processes below). See also BOURC membership
The List and published reports
Since 1956, BOURC has published reports and updates to the List in our journal IBIS (BOU 1956), with the most recent 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, published in July 2022 (BOU 2022b). All the BOURC Reports and last four editions of the British List are free to view, meaning that they can be read without requiring a subscription to Ibis, a policy decision by the BOU to ensure their widest circulation and dissemination.
Structure and processes
Since its establishment, the Committee’s structure and processes have evolved to develop a set of procedures and principles to judge each new species or subspecies for consideration 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.
All contemporary records considered for admission to the British List are first seen by BBRC who have to agree on the identification before they can be passed to BOURC. On arriving with BOURC, the Committee must initially agree with the identification and, in very rare cases where BOURC may disagree with BBRC, the record is returned to BBRC for further consideration. Usually, however, BOURC agrees with BBRC’s identification and so the Committee’s primary focus is on provenance – establishing whether the bird has a wild origin. Sometimes this is straightforward, where bird species are strongly migratory, moving large distances, rare in captivity and have been already observed as vagrants outside their natural range. However, in other cases determining whether a bird has arrived in Britain naturally is 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 important characteristic. 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 there was no evidence for long-distance migration, with instead the species being highly resident. This review of evidence played an important part in the decision to omit Paddyfield Pipit from the British List (Lees et al., 2022).
Other recent challenging species considered include Bearded Vulture Gypaetus barbatus, Mugimaki Flycatcher Ficedula mugimaki, Dalmatian Pelican Pelecanus crispus, Western Swamphen Porphyrio porphyrio and Chinese Pond Heron Ardeola bacchus, with the first two not being admitted, while the last three were (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.
Judgment is further complicated when species are widely kept in captivity in Britain and/or 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 Apus spp., being found in the captive bird trade. This means that BOURC has the challenge to distinguish, sometimes amongst a number of records, whether any can be confidently assigned to wild origins amongst the many deemed escapes. This 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 been used recently to reassess Falcated Duck Mareca falcata and Ross’s Goose Anser rossii, resulting in both species being admitted to the British List (Batty & McInerny 2022).
Reviewing previous decisions
The 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 only under two circumstances: 1) new evidence is presented (this might be in the form of a subsequent pattern of records in Britain or Europe, for example); or 2) 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, whilst a reassessment of Mugimaki Flycatcher resulted in its continued omission. The latter remains on Category D despite being 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 occurrence was too great, despite the species being a predicted vagrant (McInerny & Stoddart 2017).
A little-known function of BOURC is to identify first records of all bird species on the British List. As many of these are historical and pre-date the BBRC and BOURC period (1950 and 1883, respectively), BOURC has developed and published criteria to specifically judge such historical records, which are different to those used for contemporary first records and, in particular, must carefully consider issues of fraud that were historically prevalent among collectors (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, i.e. those species assigned to Categories A, B and C, and those species which are not on the List, i.e. 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 concerning 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 the continent, an important international collaboration allowing the consistent treatment of individuals from translocated and self-sustaining populations throughout Europe.
The following articles act as case studies about the work of the Committee (and also the British Birds Rarities Committee) on individual species, either the assessment of a first record for Britain or reviews of a group of records. These articles are usually authored by serving members BOURC (and BBRC) and serve as official documentation from the two committees.
In additional, all BOURC reports and papers can be accessed here.
Articles listed in chronological order (most recently published first).
‘Mandt’s Black Guillemot’ in Lincolnshire
Christopher McInerny & Robert McGowan. 2021. British Birds 114, 166–171
The first British record of ‘Continental Cormorant’
Robert McGowan & Christopher McInerny. 2020. British Birds 113, 418-421
The Falcated Duck in Britain
Andy Stoddart & Christopher J. McInerny. 2020. British Birds 113, 44-53
The Dalmatian Pelican in Britain
Christopher McInerny. 2019. British Birds 112, 401–404
The Elegant Tern in Britain and Europe
Andy Stoddart & Chris Batty. 2019. British Birds 112: 99-109
Bearded Vulture in northwest Europe
Christopher McInerny & Andy Stoddart. 2019. British Birds 112, 26-34
The ‘Purple Swamphen’ in Britain
Christopher McInerny & Andy Stoddart. 2018. British Birds 111, 512–514
Siberian Accentors in Europe in autumn 2016 and the first British records
Andy Stoddart. 2018. British Birds 111: 69-83
The ‘Azorean Yellow-legged Gull’ in Britain
Andy Stoddart & Christopher J. McInerny. 2017. British Birds 110, 666–674
Recent BOURC decisions: Mugimaki Flycatcher and Chinese Pond Heron
Christopher McInerny & Andy Stoddart. 2017. British Birds 110, 345–354
The Cackling Goose in Britain
Andy Stoddart. 2016. British Birds 109: 677-683
‘Eastern Black Redstart’: new to Britain
Andy Stoddart. 2016. British Birds 109: 211-219
Extralimital races of the Ring Ouzel in Britain
Andy Stoddart. 2015. British Birds 108: 97-103
The review of the record of Slender-billed Curlew at Druridge Bay, Northumberland
J. Martin Collinson, Adam Rowlands, Jimmy G. Steele, Christopher J. McInerny & Nigel Hudson. 2014. British Birds 107, 389–404
Records of House Finch in Britain
Andrew H. J. Harrop. 2014. British Birds 107, 460– 466
What the eye doesn’t see: the prevalence of fraud in ornithology
Andrew H. J. Harrop, J. Martin Collinson & Tim Melling. 2012. British Birds 105, 236–257
Status and movements of Eagle Owls in Europe
Tim Melling, Steve Dudley & Paul Doherty. 2011. British Birds 104, 544–546
A follow up letter to Melling et al 2008 below
The Eskimo Curlew in Britain
Tim Melling. 2010. British Birds 103, 80–92
Britain’s first Baikal Teal
Andrew H. J. Harrop & Robert Y. McGowan. 2009. British Birds 102, 691–696
Brown Flycatcher on Fair Isle: new to Britain
Paul Harvey. 2008. British Birds 101, 651–657
The Eagle Owl in Britain
Tim Melling, Steve Dudley & Paul Doherty. 2008. British Birds 101, 478–490
The British List and BOURC reports relating to the List are published free-to-view in our journal IBIS. Many articles relating to species admitted to, or decisions relating to, the British List are published in British Birds who kindly make these articles free-to-view a year after their publication.
- Batty, C., & McInerny, C.J., on behalf of BOURC. 2022. The Ross’s Goose in Britain. Brit. Birds 115: in-press.*
- British Ornithologists’ Union (BOU). 1883. A List of British Birds Compiled by a Committee of the British Ornithologists Union. John van Voorst: London.
- British Ornithologists’ Union (BOU). 1915. A List of British Birds (Second and Revised Edition). London: BOU.
- British Ornithologists’ Union (BOU). 1956. British Ornithologists’ Union British records sub-committee: first report. IBIS 98: 154-157
- British Ornithologists’ Union (BOU). 2018. British Ornithologists’ Union Records Committee (BOURC): 49th Report (October 2018). IBIS 160: 241-248
- British Ornithologists’ Union (BOU). 2022a. British Ornithologists’ Union Records Committee (BOURC): 54th Report (July 2022). IBIS 164: 929-931.
- British Ornithologists’ Union (BOU). 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.
- McInerny, C.J., & Stoddart, A., on behalf of BOURC. 2017. Recent BOURC decisions: Mugimaki Flycatcher and Chinese Pond Heron. British Birds 110: 345-354.
- McInerny, C.J., & Stoddart A., on behalf of BOURC and BBRC. 2018. The Western Swamphen in Britain. Brit. Birds 111: 512-514.
- McInerny, C.J., & Stoddart A., on behalf of BOURC and BBRC. 2019. Bearded Vultures in north-west mainland Europe and Britain. Brit. Birds 112: 26-34.
- McInerny, C.J., Crochet, P.-A., Dudley, S.P., on behalf of BOURC & 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.
* Will be made free to view by British Birds a year after publication.
This article has been adapted from one written by BOURC Secretary, Chris McInerny, for British Birds (Brit. Birds 115: 542–545).
We thank British Birds for making BOURC-related content published in BB available free-to-view.