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2003 News and Decisions

from the Records Committee (BOURC)

5 December 2003

BOURC Taxonomic Sub-committee announces important taxonomic decisions relating to the British List

The Taxonomic Sub-committee (TSC) of the British Ornithologists’ Union Records Committee (BOURC) has recently completed work on a series of taxonomic recommendations relating to the British List.

A full report of the current recommendations, with supporting information, will appear in the January 2004 issue of Ibis (Ibis 146: 153-156). Amongst the recommendations are the following:

Tundra Swan Cygnus columbianus. Bewick’s Swan Cygnus c. bewickii and Whistling Swan C. c. columbianus should continue to be treated as conspecific.

Pied Wheatear Oenanthe pleschanka to be treated as two species, Pied Wheatear O. pleschanka and Cyprus Wheatear O. cypriaca. Only O. pleschanka has been recorded in Britain.

Desert Warbler Sylvia nana to be treated as two species, Asian Desert Warbler S. nana and African Desert Warbler S. deserti. All British records have been assigned to S. nana.

Red-breasted Flycatcher Ficedula parva to be treated as two species, Red-breasted Flycatcher F. parva and Taiga Flycatcher F. albicilla. Two recent records of Taiga Flycatcher are under consideration.

Pied Flycatcher Ficedula hypoleuca. Atlas Flycatcher to be treated as a full species Ficedula speculigera. There are no claims of this species in Britain, but the recommendation clarifies the world distribution of F. hypoleuca.

The full list of recommendations in the Taxonomic Sub-committee's forthcoming report have been accepted by the BOURC, and will be implemented when formally published in the January 2004 issue of the BOU’s journal, Ibis (Ibis 146: 153-156).

The BOURC-TSC has also been working with the Association of European Rarities Committees Taxonomic Advisory Committee (AERC-TAC), which has recently posted taxonomic information on the AERC website (http://aerc.be/aerc_tac.htm).

The AERC-TAC document includes a series of taxonomic recommendations for European birds. As the document clearly states, this is not a final version. Many items and opinions expressed in the document are still being discussed or have not yet been agreed among the European taxonomic committees.

Although the BOURC-TSC is listed as a contributor of the document, the contents of the current version are not supported by the BOU, nor are they supported by all the other European taxonomic committees, e.g. the Commissie Systematiek Nederlandse Avifauna (CSNA) are issuing their own statement to this effect. The AERC-TAC recommendations do not affect the British List. The report of BOURC-TSC, which is published in Ibis, remains the official publication of the BOU.

For further information, you can contact –

29 May 2003

Caspian Gull

Larus argentatus cachinnans

Added to Category A of the British List

The British Ornithologists’ Union Records’ Committee (BOURC) has added Caspian Gull Larus argentatus cachinnans to Category A of the British List following the acceptance of a bird seen at Mucking, Essex on 4 September 1995.

Dealing with a series of records, the problem faced by the BOURC was to establish which of the records could be accepted, unequivocally, as the first for Britain. Interest in the ‘large white-headed gull’ complex has increased enormously in recent years resulting in a series of papers dealing with identification criteria for L. a. cachinnans and other taxa within the group.

During circulation of the records, discussion revolved around three issues. Firstly, we had to be aware of the dangers of basing our perceived knowledge of the identification of this taxon purely on records of vagrant birds. Secondly, the question arose of possible intergradation may occur between taxa within the group and thirdly, a decision was required on just which criteria were essential to establish a particular individual as a first for Britain.

The committee considered that the identification characteristics of L. a. cachinnans were now well-established on the basis of papers relating to birds of known provenance. They also considered that it will never, in practice, be possible to eliminate the possibility of the genetic influence of some other taxon in any individual and that the only pragmatic solution is to accept records of cachinnans provided that an individual displays no anomalous characters. On the question of just which were the necessary criteria for acceptance, a majority of the committee felt that a description of the pattern of the 10th primary (on adults) was essential in addition to all the other well-documented ‘jizz’ characters. On that basis, an earlier record from Mucking on 16 August 1995 was thought to not quite meet the rigorous standards to be accepted as the first record for Britain, but that the record of 4 September did.

Debate on the taxonomy of the ‘large white-headed gull’ complex continues and the BOURC is well aware that its continued treatment of Caspian Gull as a race of Herring Gull is no longer considered valid by many observers. The taxonomic status of Caspian Gull (and related taxa) is currently under active investigation by the Committee's Taxonomic Sub-committee.

This decision does not affect the British List totals and the number of species on the British List remains 565 species (Category A = 542; Category B = 14; Category C = 9).

For further information, you can contact –

This is a joint press release of:

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31 January 2003

Ascension Frigatebird

Tiree, Inner Hebrides, Scotland

9 July 1953

Added to Category A of the British List

The British Ornithologists’ Union Records Committee (BOURC) has added Ascension Frigatebird Fregata aquila to Category A of the British List following the reidentificaton of a bird found moribund on the island of Tiree, Inner Hebrides, Argyllshire, Scotland on 9 July 1953 (sight record, specimen) and originally identified as Magnificent Frigatebird Fregata magnificens. With no other records, Magnificent Frigatebird is therefore removed from the British List.

The bird, an immature female, was found exhausted on 9 July 1953 and died later the same day. The body was taken to the National Museum of Scotland where it remained for nearly fifty years, its identity as Magnificent Frigatebird unquestioned.

The record was recently reviewed by the British Birds Rarities Committee (BBRC) following a decision by the Association of European Rarities Committees (AERC) to bring European rarities committees into line with a standard date of 1950 for Category A records. Prior to this, the accepted date for Category A in Britain was 1958, the date when BBRC was formed. During the circulation, BBRC members Brian Small and Grahame Walbridge suspected a misidentification and undertook detailed research to confirm the identity as Ascension Frigatebird. Identification of immature frigatebirds is not straightforward and this research broke new ground.

At the same time that Magnificent Frigatebird is removed from the British List, it is added to the Isle of Man List following the discovery of an exhausted bird at Scarlett Point, Castletown, on 22 December 1998. The bird, an adult female was taken into care, where it died 10 months later (October 1999). The detailed description plus photographs left no doubt that the bird was correctly identified, though unfortunately the corpse was not retained. Thankfully the original observers of the Tiree frigatebird sent the body to a museum otherwise Ascension Frigatebird would have been denied its rightful place on the British List.

There will be a full paper appearing in British Birds outlining this remarkable event.

These changes mean that the British List remains on 565 species (Category A = 542; Category B = 14; Category C = 9).

For further information, you can contact –

This is a joint press release of:

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