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The British List

BOU Species categories

In 1997 categorisation was revised to assist protection under national wildlife legislation, especially of naturalised species. Category C has been expanded to allow species with different histories to be distinguished; Category D has been reduced in scope, and a Category E (not included in this list) has been introduced to enable local and national recorders to monitor escaped species.

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

B   Species that were recorded in an apparently natural state at least once between 1 January 1800 and 31 December 1949, but have not been recorded subsequently.

C   Species that, although introduced, now derive from the resulting self-sustaining populations.

C1 Naturalized introduced species – species that have occurred only as a result of introduction, e.g. Egyptian Goose Alopochen aegyptiacus

C2 Naturalized established species - species with established populations resulting from introduction by Man, but which also occur in an apparently natural state, e.g. Greylag Goose Anser anser

C3 Naturalized re-established species - species with populations successfully re-established by Man in areas of former occurrence, e.g. Red Kite Milvus milvus

C4 Naturalized feral species - domesticated species with populations established in the wild, e.g. Rock Pigeon (Dove)/Feral Pigeon Columba livia .

C5 Vagrant naturalized species - species from established naturalized populations abroad, e.g. possibly some Ruddy Shelducks Tadorna ferruginea occurring in Britain. There are currently no species in category C5.

C6 Former naturalized species – species formerly placed in C1 whose naturalized populations are either no longer self-sustaining or are considered extinct, e.g. Lady Amherst's Pheasant Chrysolophus amherstiae .

D   Species that would otherwise appear in Category A except that there is reasonable doubt that they have ever occurred in a natural state. Species placed in Category D only form no part of the British List, and are not included in the species totals.

E   Species that have been recorded as introductions, human-assisted transportees or escapees from captivity, and whose breeding populations (if any) are thought not to be self-sustaining. Species in Category E that have bred in the wild in Britain are designated as E*. Category E species form no part of the British List (unless already included within Categories A, B or C).

F   Records of bird species recorded before 1800.

F1  Records of bird species recorded between c. 18000 BP (before present) to 1800

F1.1	1500 – 1800	Post Medieval
F1.2	1100 – 1500	Medieval
F1.3	400 – 1100	Anglo-Norman
F1.4	0 – 400	Roman
F1.5	c. 3500 BP – 0	Iron Age
F1.6	c. 45000 – c. 3500	BP Bronze Age
F1.7	c. 6000 – c. 4500	BP Neolithic
F1.8	c. 11000 – c. 6000	BP Mezolithic
F1.9	c. 18000 – c. 11000	BP Late Glacia

F2  Records of bird species recorded earlier than 16000 BP, back to c.700,000 BP

F3  Specimens or records of uncertain species or date

Each of the above can be further subdivided to denote (a) fossil or bone specimen and (b) documentary only records, e.g.

F1.1a = A fossil or bone specimen record from between 16000 BP to 1800 AD

F1.1b = A documentary only record from between 16000 BP to 1800 AD

A species is usually placed in only one category, but some are placed in multiple categories, for example, those species occurring in Category A which now have naturalised populations (e.g. Red Kite).

The British List comprises only those species in Categories A, B and C.

The newly created Category C6 recognises that some previously established naturalized introductions to Britain have declined (and others may do so in the future) to a level that is no longer self-sustaining, and which will ultimately lead to extinction. Further releases of such non-native species are prohibited under Section 14 of the Wildlife & Countryside Act 1981

The 'Official' British List

The following organisations have indicated their support for the work undertaken by the BOU and its Records Committee in maintaining a list of birds recorded in Britain. They have indicated that the decisions on both status and taxonomy reached by BOURC are accepted by them as comprising the 'official' British List.

• British Trust for Ornithology • Countryside Council for Wales • English Nature • Joint Nature Conservation Committee • Royal Society for the Protection of Birds • Scottish Natural Heritage • Scottish Ornithologists' Club • Wildfowl & Wetlands Trust • The Wildlife Trusts

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