A new unified global checklist of birds
In 2021, representatives of the American Ornithological Society, Avibase, Birdlife International, the Cornell Lab of Ornithology and the International Ornithologists’ Union began a collaboration, the intention being to agree a unified global checklist of birds. This would involve reconciling the differences in the scientific names of species between three major world checklists: Birdlife International, Clements and the International Ornithological Congress.
As a basis, it was agreed to use an ‘integrative species concept’. This would take into account morphology, behaviour, ecology, genetics, phylogenetic relations, time since divergence, biogeographical distribution and any evidence of reproductive isolation. It would include analysing some recordings of breeding songs, inspecting certain museum specimens for plumage differences and considering the latest DNA research with genome sequencing.
There were twenty-three core team members when, on 11 June 2025, the unified checklist was published on line at www.avilist.org/checklist/v2025. The checklist is known as AviList and contains 11,131 species plus all currently recognised subspecies. Although species’ English names are used, these are not intended to be necessarily adopted even within the English-speaking parts of the world; it is the species’ scientific names that have been unified.
The group’s work will continue into the future as the current consensus on species and subspecies will inevitably change. Reviews are intended to be published annually. New scientific research will become available that sheds even more light on the evolutionary relationships of birds, while the birds themselves will keep changing too. Pamela Rasmussen, one of the core team members, sums it up: ‘Evolution’, she says, ‘is a work in progress’.
Taxonomy sequence and nomenclature
In the UK, the British Ornithologists’ Union (BOU) is the keeper of The British List and it is this, in its simple list format, that we follow in East Glamorgan. Since 2017, The British List in its simple list format has followed the taxonomy and sequence of the International Ornithological Congress’s world list: the IOC World Bird List. Because of the publication of a unified global checklist and the IOC’s participation in its compilation, however, the BOU has decided to endorse the taxonomy and sequence of AviList and followed AviList v2025 in its latest report. The East Glamorgan Bird List will follow suit, again in the BOU’s simple list format as far as nomenclature is concerned.
The most recent publication of the full British List is the British Ornithologists’ Union (BOU). The British List: A Checklist of Birds of Britain (10th edition) which can be viewed on the BOU website at www.bou.org.uk and in Ibis 164:860-910.
The BOU’s publication has since been somewhat superseded: the BOU has revised on its website at www.bou.org.uk its British List simple list format (January 2025). Within the updated East Glamorgan bird list below, the taxonomy, sequence and nomenclature follow this simple list format. The recent publication of the East Glamorgan Bird Report No. 63, covering 2024, has triggered the compilation of the updated East Glamorgan bird list below, so the species within the list are those recorded in East Glamorgan up to the end of 2024.
CLICK HERE TO VIEW THE CURRENT LIST – uploaded on 26 Jan 2026
The updated East Glamorgan bird list
AviList, and therefore the BOU’s British List, has combined as two single species two pairs of birds recorded in East Glamorgan and formerly considered to be separate species, namely (Common) Teal and Green-winged Teal and Carrion Crow and Hooded Crow, so the East Glamorgan bird list is reduced by two species. Another pairing of two previously-considered separate species concerns Balearic Shearwater and Yelkouan Shearwater; however, although Balearic Shearwater has been recorded in East Glamorgan Yelkouan Shearwater has not, so this pairing has no effect on the number of species on the East Glamorgan bird list but it does mean a change of name for the pair to ‘Mediterranean Shearwater’.
An American Golden Plover seen at Sker Point from 2nd to 5th April 2024 was a new species for the recording area.
As a result of the teal and crow taxonomic changes and the addition of American Golden Plover, the total number of species recorded in East Glamorgan reduces by one to 320.
Other than six BOU Category C species (Egyptian Goose, Mandarin Duck, Ruddy Duck, Pheasant, Red-legged Partridge and Little Owl), all of the species recorded in East Glamorgan are BOU Category A species.
For each of the species on the East Glamorgan bird list, the year in which it was first recorded, if known, is included. Of the 320 species, 244 were recorded from 2020 to 2024 inclusive; for each of the remaining 76 species, the year in which it was last recorded is also included.
The entire list is tabulated in a pdf file linked to above.
Glamorgan Bird Club 