BTO supports the taxonomic listing recommended by the British Ornithologists’ Union (BOU) in its British List. We follow this authoritative listing so that our bird data can be interpreted more easily, at home and internationally.
What is taxonomy?
Taxonomy is the study of the classification and scientific naming of living things.
Taxa include large units, such as kingdoms and families, and smaller ones such as genera, species and subspecies.
A 'tree of life' has existed since the time of 19th-century naturalist Charles Darwin but the model is constantly changing as:
- Science uncovers new relationships between taxa, or disproves others.
- New species are discovered, even among birds, in the field or in museum collections.
- Consensus changes on where the boundaries between species should be drawn.
- Expert opinion changes on how data should be interpreted and uncertainties managed.
What is a taxonomic order?
In a 'taxonomic' or 'systematic' list of birds, species are placed in a linear sequence according to how long ago they are thought to have evolved, oldest first. Related taxa are grouped together.
BTO supports the BOU taxonomic listing
BTO supports the taxonomic listing recommended by the British Ornithologists’ Union (BOU) in its British List (PDF). By following the latest BOU listing we are keeping up to date and so the lists we present are always scientifically defensible.
Most of BTO's online applications draw upon a single live table of bird names, including their systematic order, that resides in our database. We normally update this table in the weeks or months following a BOURC report, unless there is reason to delay.
Lists including Ireland
BTO extends the BOU's list as necessary to cover UK and the whole of Ireland – although there are minor differences between the official lists for Britain and for Ireland and no agreed list for the UK or for Britain and Ireland together. We are pragmatic about naming and ordering those non-native species that are recorded on surveys but which are not listed by BOU.
Alphabetically ordered alternative
Ordering and naming of species is rarely static for more than a year, meaning that people looking to contribute data to BTO or to find information in reports need to be aware of recent changes.
An alphabetically ordered species list is provided as an option by several of our online applications, including BirdTrends and BirdTrack, so that users can bypass the taxonomic listing if they prefer.
BOU’s British List – process
The British List is updated annually by the BOU's Records Committee (BOURC), who take on the tasks of incorporating the latest research and taxonomic thinking, and of furthering the search for international agreement (through AERC and IOU). BOU also recommends English names for British birds.
- The Taxonomic Sub-committee (TSC) of BOURC publishes recommendations for taxonomic adjustments in their periodic reports in Ibis.
- The reports of BOURC, also in Ibis, incorporate any relevant TSC recommendations alongside other, non-taxonomic issues.
- The publication of the BOURC report, normally online in December and in print in January, marks the adoption of the TSC recommendations and makes them official.
For an introduction to the aims and practices of BOU's systematic list of British birds, read British Ornithologists’ Union (2013) The British List: A Checklist of Birds of Britain (8th edition). Ibis 155: 635–676 (though this is no longer the latest list).
Why the constant changes?
Changes to BOU's British List reflect ongoing developments in the scientific understanding of avian evolution. Previous versions of the List are discarded because they are no longer believed to be correct.
The main driver of change has been the introduction of molecular taxonomy, typically using DNA, to replace the previous wholly phenetic approach (based on observable traits). An initial broad-scale re-ordering of birds in the 1990s, using DNA–DNA hybridisation, is gradually being revised using ever-more powerful techniques.
Recent changes to the British List
- Genetic analyses have revealed that falcons are not closely related to the other diurnal raptors, as had long been assumed, but instead are more closely related to the parrots. The parrots and falcons are more closely linked to the passerines than are any other groups. As a result, the position of these groups in a taxonomic sequence has been changed, with the falcons (Falconiformes) and parrots (Psittaciformes) now positioned between the woodpeckers (Piciformes) and the passerines (Passeriformes).
- The finches (family Fringillidae) have undergone a significant revision. In addition to a change in sequence, of most immediate relevance there are changes to the generic names for Linnet and Twite (now Linaria), the redpolls (now Acanthis), Siskin (now Spinus) and Common Rosefinch (now Erythrina).
- Re-ordering of Galliformes, placing grouse after Quail and Red-legged Partridge but before Grey Partridge and pheasants.
- Full re-ordering of the sequence of sub-orders, families and genera within the Charadriiformes (now in the order waders, skuas, auks, terns and gulls).
- Within the scolopacid Charadriiformes, a complete review of the genus Calidris, now expanded to include Ruff and Buff-breasted and Broad-billed Sandpipers, with Ruff placed after the knots, and the stints and small sandpipers no longer placed together.
- A new sequence for chats and flycatchers, interposing robins, nightingales and others between Spotted and Pied Flycatchers.
- Greenfinch removed from Carduelis to its own genus Chloris, with a consequent shift of position in the list.