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2001 News and Decisions

from the Records Committee (BOURC)

21 December 2001

Hooded Merganser

Oban Trumisgarry Loch, North Uist
23 October to 1 November 2000

BOURC has voted to add the above record to Category D (species that would otherwise appear in Category A except that there is reasonable doubt that they have ever occurred in a natural state).

The location and timing of the finding of the bird, in favourable weather conditions and during a period with large numbers of Nearctic migrants arriving in Europe, suggested natural vagrancy. Although the bird, a female, was claimed to be a first-winter by some observers, following careful examination of photographs, video footage and descriptions, the Committee concluded that it was of undeterminable age.

The species’ range and abundance in North America, and the question of captive status, were investigated thoroughly.

The species is relatively rare in North America, particularly in the eastern part of its range, compared with other species of duck which have occurred in Britain from the same area (see, for example, Birding World 10: pages 73-75 (1997) which gives the following comparison of populations: Lesser Scaup 8 million, Canvasback 900,000, Redhead 800,000, and Hooded Merganser 80,000. The editors add that half the population of Hooded Mergansers is semi-resident on the west coast).

The species is well known as being kept and bred commonly in captivity across Europe. The 1998 British Waterfowl Census listed for 1997 (the last year for which figures are available) a total of 51 keepers with 329 birds and reports that 92 females produced fertile eggs. These censuses very much underestimate the true totals of Hooded Mergansers in captivity in the UK as there is no requirement for keepers to register their birds. In The Netherlands, rather older figures, but equally indicative of the scale of the captive bird situation, are given in Dutch Birding 15: page 276 (1993) which reported that members of the Bird Keepers’ Association reared 637 young Hooded Mergansers in 1989 and 1,437 in 1991, adding that the actual numbers were estimated to be two or three times higher (Paul Vassen pers. com.)

One colour-ringed escape has reached Iceland, where they are unknown in captivity. Similarly, colour-ringed birds have been seen in western Ireland and western Britain in locations and on dates which might have indicated wild origin (including one during the same period as this bird).

It is generally accepted that most Nearctic vagrants are birds in their first winter, more likely to wander off-course on their first migration than experienced adults. Regardless of age, the background of captive birds will always make record assessment difficult, even for immatures.

Against this background of relative rarity in eastern North America, the large numbers kept in captivity in Europe, and the uncertainty over the age of the bird, BOURC took the cautious view that the record should be placed in Category D. This is a holding category which allows for reconsideration at a later date in the light of further records, in Britain or in Europe, or of changes in distribution, abundance or vagrancy.

11 December 2001

Additions to the British List

The following additions have been made to the British List and take effect when published in Ibis.

Add to Category A

Mourning Dove Zenaida macroura
Carinish, North Uist, Outer Hebrides, first-winter, photographed, 13-15 November 1999.
The identification of this bird, in a location and on a date indicative of a wild vagrant, was accepted without question. The captive status of the species was investigated and with very few being held in collections, the possibility of it being an escape was considered unlikely. This constitutes the first British record of the species.
    There is a record of a first-winter bird found in a Heligoland trap at the Calf of Man Bird Observatory, Isle of Man, on 31 October 1989, and found dead the next day, but records from the Isle of Man do not form part of the British List. There is an earlier Western Palearctic record of a first-winter female collected on Heimaey, Iceland, on 19 October 1955.

Rufous Turtle Dove Streptopelia orientalis meena
Spurn, Yorkshire, first-winter, photographed, 8 November 1975.
This record was accepted by BBRC, but not assigned to race. Publication of the record in Rare and Scarce Birds in Yorkshire (Wilson & Black, 1996) stated that it was considered to be of the western race meena. The previous four records were racially undetermined, or were of the eastern race orientalis.
   A decision on racial separation based on the current literature proved to be difficult, and the Committee examined skins from the Natural History Museum at Tring. This enabled them to unanimously agree that the bird belonged to the race meena, and this is therefore becomes the first British record of this race.

7 December 2001

Major changes in European Taxonomic Committee

At its Conference held in Poland in September, the Association of European Rarities Committees (AERC) agreed major changes in the structure, operation and accountability of its Taxonomic Advisory Committee (TAC). This resulted from proposals put forward jointly by the British Ornithologists’ Union Records Committee (BOURC) and British Birds Rarities Committee (BBRC) with the aim of more effectively co-ordinating and accelerating avian taxonomic decision-making across Europe.

The previous TAC of four members from three countries has been replaced by a new TAC of five members, one from each of the countries which has its own taxonomic committee, under a Chairman who is neither a taxonomist, nor from any of those five countries.

The British representative on the new TAC is Dr Martin Collinson, who is Secretary of the BOURC’s Taxonomic Sub-committee (TSC). The Chairman of the new TAC is Gunter De Smet, who is Chairman of the Dutch-speaking section of the Belgian Rarities Committee and a member of the Editorial Boards of both Dutch Birding and Oriolus.

Full details of the new European structure, its terms of reference and its membership, can be found in the Minutes of the AERC’s Sixth Conference which are posted on the AERC website at – (www.birding.yucom.be/AERC/Hel_2001.htm

1 October 2001

The BOURC’s Taxonomic Sub-committee (TSC) has been obtaining and reviewing a considerable volume of new information on the species currently under review, with progress made on many issues which should facilitate future decisions. For some taxa, essential data are lacking, or have not yet been published. In some cases, we anticipate publication in the near future of relevant information. The following is a progress report.

Species definitions

The Taxonomic Advisory Committee (TAC) of the Association of European Rarities Committees (AERC) and the BOURC’s TSC have been jointly developing general principles and species criteria on which taxonomic recommendations are to be made. The questions of species concepts and ground rules to define and delimit species have been addressed in detail, and draft guidelines have been prepared. These are being trialled on a variety of taxa, and are being refined in the light of that experience. They are an essential prerequisite to making recommendations.

Taxa under review

The following paragraphs summarise the current situation for taxa which have received the most attention.

Tundra (Bewick’s/Whistling) Swan – Cygnus columbianus columbianus/bewickii
These two taxa differ in the amount of yellow on the bill, but whether this warrants specific status needs further study.

Bean Goose - Anser fabalis/serrirostris
A Bean Goose Complex Task Force is currently working in Europe, which includes genetic studies within its remit. Its conclusions are awaited.

Brent Goose – Branta bernicla bernicla/hrota/nigricans
The taxonomy of this complex is intriguing and still only partly resolved. A careful reassessment of published papers is being used to judge these taxa against the agreed species criteria.

Common and Velvet Scoter – Melanitta nigra/M. fusca
These taxa are being actively addressed, with a review in preparation.

Common/Wilson’s Snipe – G.g.gallinago/delicata
The two taxa differ in auditory signals (i.e. drumming sounds), but uncertainty still surrounds the degree to which they are diagnosably different in plumage. The status of these taxa is being actively investigated.

‘Yellow-legged’ Gull – Larus argentatus michahellis/ L. a. cachinnans
This lively issue has not yet been resolved. Data concerning the breeding behaviour of michahellis and argenteus in Western Europe are well documented, but much of the published literature regarding the situation in Eastern Europe is anecdotal. Publication of an important peer-reviewed paper in the next few months is anticipated and is keenly awaited.

Yellow and White Wagtails – Motacilla spp.
The situation is complicated by the large number of subspecies under review. There is evidence that some of the subspecies relevant to the British List may fulfil some species criteria. At least two independent research groups are close to publishing genetic analyses of the relationships between various taxa within Motacilla. No decision is possible before these results are accepted for publication.

Red-breasted/Red-throated Flycatcher – Ficedula p. parva/ F. p.albicilla
The paper by Cederroth et al (Birding World 12, 460-468) presented evidence that these taxa deserve separate specific status. Further molecular data (in press) should clarify the situation.

Carrion/Hooded Crow – Corvus corone corone/cornix
These taxa are being actively addressed, with a review in preparation.

Notes

1. The AERC’s TAC consists of Dr Andreas Helbig, Dr Alan Knox, Professor David Parkin and George Sangster.

2. The BOURC’s TSC includes the above plus Dr Martin Collinson (Secretary) and Dr Tony Prater (Chairman).

9 June 2001

BOURC annual summer meeting, 9 June 2001, Egleton Village Hall, Rutland. Present from left to right: Roger Wilkinson, Eric Meek, Andrew Harrop, Ian Lewington (kneeling), Tony Prater, Bob McGowan, Tim Melling (Secretary), Tony Marr (Chairman) and Steve Dudley (BOU Administrator). Paul Harvey and Colin Bradshaw (Chairman, BBRC) were unable to attend the meeting. Photo: Tim Appleton.

May 2001

In May 2001, Alan Knox retired from the BOU’s Records Committee after 16 years of continuous service, including time as Chairman. Here, Tony Marr, current BOURC Chairman, presents Alan with a copy of Albatrosses in recognition of his long service to the BOU and to British ornithology.

9 January 2001

The BOURC’s 27th Report, covering the period from October 1999 to September 2000 inclusive, has just been published in Ibis 143: 171-175 (January 2001). A copy is attached. Some of the decisions announced in the Report have already been publicised in previous press releases. Attention is drawn to the following decisions, based on recent reviews, and not previously announced.

  • Hooded Merganser Lophodytes cucullatus – deleted from the British List
  • Bufflehead Bucephala albeola – remains in Category A of the British List
  • Asian Brown Flycatcher Muscicapa dauurica – remains in Category D
  • Mugimaki Flycatcher Ficedula mugimaki – remains in Category D
  • Palm Warbler Dendroica palmarum – deleted from Category D

The reasons for these decisions are set out in the Report.

Attention is also drawn to the list of files under consideration. Please note that subsequent to this Report going to press, a press release dated 22 December 2000 announced the addition to Category A of one new species, Short-billed Dowitcher Limnodromus griseus, and two new sub-species, Black Tern Chlidonias niger surinamensis and Nightingale Luscinia megarynchos hafizi, to the British List. These decisions will be published in the BOURC’s 28th Report to appear in Ibis 144, January 2002.

The decisions published in the Report and recently announced in our press release of 22 December 2000 (see above), bring the number of species on the British List to 556, with five species (Green-winged Teal Anas carolinensis, Short-toed Eagle Circaetus gallicus, Short-billed Dowitcher Limnodromus griseus, Iberian Chiffchaff Phylloscopus brehmii and Lesser Redpoll Carduelis cabaret) added to Category A and the removal of one species (Hooded Merganser Lophodytes cucullatus) from the British List.

  • A 534
  • B 13
  • C 9
  • Total 556

The total does not include 'soft-plumaged petrel' Pterodroma mollis/P. madeira/P. feae as the birds were not identified to species level (Ibis 134: 380). The 15 species in Category D and those species in Category E do not form part of the British List.

For further information please contact:

Tony Marr, Chairman, BOURC Tel 01 263 741 313 Email bourc.chair@bou.org.uk
Tim Melling, Secretary, BOURC Tel 01 484 861 148 Email bourc.sec@bou.org.uk
Steve Dudley, BOU Administrator Tel 01 733 390 392 Email steve.dudley@bou.org.uk

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