BRITISH ORNITHOLOGISTS' UNION

Press Release 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.

Press Release   11 December 2001

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.

For further information, please contact:

Tony Marr, Chairman, BOURC 
Tel 01 263 741 313  
E-mail bourc.chair@bou.org.uk

Tim Melling, Secretary, BOURC  
Tel 01 484 861 148 
E-mail bourc.sec@bou.org.uk

Steve Dudley, BOU Administrator  
Tel 01 733 390 932   
E-mail steve.dudley@bou.org.uk

BRITISH ORNITHOLOGISTS' UNION
The Natural History Museum, Tring, Hertfordshire HP23 6AP, UK
Tel +44 (0) 1 442 890 080  Fax +44 (0) 20 7942 6150  Email bou@bou.org.uk

The British Ornithologists' Union, founded in 1858, is one of the world's oldest ornithological societies. The BOU's main function is to "promote ornithology within the scientific and birdwatching communities". This is achieved primarily by the publication of BOU's international journal of avian science, Ibis, one of the world's leading ornithological journals. Ibis includes original research reports on the systematics, ecology, physiology, behaviour, anatomy and conservation of birds. Ibis is also available online at www.ibis.ac.uk. The BOU also organises conferences, seminars, meetings and expeditions and gives a series of annual grants and awards to assist with travel and equipment associated with ornithological research projects and student sponsorship.

The British List

For over 100 years the British Ornithologists' Union (BOU) has maintained a list of birds that have been recorded in Britain. This is undertaken by the BOU's Records Committee (BOURC), which periodically publishes up-to-date checklists incorporating changes the BOURC has announced in its reports published annually in the BOU's journal, Ibis.

In 1997, the BOURC liaised with the government's Joint Nature Conservation Committee (JNCC) to revise the categories used in the British List. The JNCC has adopted the list for decisions concerning to the status of birds in Britain in relation to the Wildlife and Countryside Act 1981.

Responsibility for the British list lies with the BOURC. Northern Ireland has different legislation, and the list for Northern Ireland is maintained by the Northern Ireland Birdwatching Association (NIBA). The Isle of Man (which is not a legislative part of the UK) also maintains its own list which may be used by its own legislators.

Species recorded from the Republic of Ireland do not form any part of the British List

Categories used in the British List

A   Species which have been recorded in an apparently natural state at least once since
1 January 1950.

B   Species which were recorded in an apparently natural state at least once up to
31 December 1949, but have not been recorded subsequently.

C   Species that, although originally introduced by man, either deliberately or accidentally,
have established breeding populations derived from introduced stock, that maintain
themselves without necessary recourse to further introduction.

C1                 Naturalised introductions Species that have occurred only as a result of
introduction. E.g. Egyptian Goose Alopochen aegyptiacus.

C2                 Naturalised establishments Species with established populations as a result
of introduction by Man, but which also occur in an apparently natural state.
E.g. Canada Goose Branta canadensis.

C3                 Naturalised re-establishments Species with populations successfully
re-established by Man in areas of former occurrence.
E.g. Red Kite Milvus milvus.

C4                 Naturalised feral species Domesticated species with populations established
in the wild. E.g. Rock Dove Columba livia.

C5                 Vagrant naturalised species Species from established naturalised populations
abroad. E.g. some/all Ruddy Shelducks Tadorna ferruginea occuring in
Britain.

D   Species that would otherwise appear in Categories A or B except that there is reasonable
doubt that they have ever occurred in a natural state. Category D species are included within
the lists that follow. They do not form any part of the species totals, and are not regarded as
members of the British List.

E    Species that have been recorded as introductions, transportees or escapees from captivity,
and whose breeding populations (if any) are thought not to be self sustaining. Category E
species form no part of the British List.

The role of the BOURC

Records of birds new to Britain are passed to the BOURC by the British Birds Rarities Committee (BBRC) after that committee has examined them. The BOURC Secretary prepares a file summarising the record. The file also contains original descriptions and supporting documentation, including BBRC comments, correspondence from independent specialists, an analysis of the captive status of the species and its escape likelihood and extracts from books and journals referring to migration and vagrancy patterns. Records are circulated by post and require unanimous agreement on identification and at least a two-thirds majority on categorisation. All files are archived for future reference.

The Committee also studies taxonomic advances and initiates research into this field. Information on feral populations is monitored, and reviews are undertaken of older records. Anyone can ask for old or rejected records to be reviewed by the BOURC if they provide fresh evidence to justify re-examination.

This is time-consuming work, particularly when it involves detailed research or discussions with experts, who are often based abroad.

Publication of BOURC decisions

The BOURC publishes regular reports in Ibis, the BOU's scientific journal. As few birders regularly see Ibis, information is press-released to the main birding magazines, who also receive pre-publication copies of the Ibis reports. The magazines use some of this information as the basis for news items or articles, but much of the BOURC's work goes unreported. BOURC members occasionally write longer papers on species reviews and decisions for publication in the birding magazines. Decisions are notified to appropriate recorders and/or the original observers.