Andrew Stanbury updates us on the latest Birds of Conservation Concern update
Few wildlife spectacles are more impressive as a busy seabird colony in the height of the breeding season. Whether that be a large gannetry, tern or auk colony, the sights and smells staying with you forever. The UK’s breeding seabirds are, however, in trouble. Today, sees the publication of updated ‘Birds of Conservation Concern’ assessments for 28 of our seabirds in the journal British Birds. Unfortunately, the results are alarming with many UK seabird populations in severe decline.
What is ‘Birds of Conservation Concern’?
First, I should explain what ‘Birds of Conservation Concern’ assessment represent. Commonly shorted to ‘BoCC’, it is a well-established, well-respected process for identifying conservation priorities for birds in the UK, Channel Islands and Isle of Man. It uses quantitative assessments against standardised criteria to allocate species into one of three lists, ‘Red’, ‘Amber’ or ‘Green’, depending on their level of conservation concern; with those that have either suffered severe declines, or are threatened with global extinction, appearing on the Red list of species of the highest conservation concern. The first review to use this traffic light system was published in 1996. Since the it has been repeated, roughly every six years.
BoCC5, the 5th edition, was published in 2021; however, owing to delays in fieldwork on the seabird census, Seabirds Count, caused by the Covid 19 pandemic, we were unable to update the status assessments for most of the UK breeding seabirds. The new seabird census is now published, and we have used this wealth of new knowledge, along with other information, including information on the severe and devastating impacts of Highly Pathogenic Avian Influenza (HPAI i.e. bird flu), to update the status assessments for all UK breeding seabirds.
What do the results shown?
Over the past 30 years, the various BoCC reviews have consistently shown a continuing decline in the status of UK bird populations and a growing Red list. This seabird specific addendum continues this trend, revealing yet further deterioration in the status of the UK’s breeding seabirds since they were last comprehensive assessed in 2015.
Arctic Tern Chantal Macleod-Nolan (rspb-images.com)
Five species join the UK Red list of species of the high conservation concern: Leach’s Storm-petrel, Common Gull, Great Black-backed Gull, Arctic Tern and Great Skua. All these species show severe population declines of greater than 50%. In the case of Great Skua, this is due to the devastating impacts of bird flu, with numbers down over 70%. These species join the likes of Kittiwake, Herring Gull, Roseate Tern, Arctic Skua and Puffin which all remain on the UK Red list. Overall, the number of Red-listed seabird species has increased from one in 1996 and 2002, Roseate Tern (BoCC1 & 2) to 10 today; 38% of the seabirds assessed (Figure 1).
Fig. 1. Length of the Red, Amber and Green lists across the five BoCC reviews for the 28 UK breeding seabirds. Note that the assessment process has developed over time and this figure does not take account of changes to criteria. Yellow-legged Gull was added to the species list in BoCC3.
On a slightly more positive note, Shag moved from Red to Amber and Black Guillemot moved from Amber to Green, however, both these changes are due to improved knowledge showing lower rates of decline, rather than increases in population or range. The UK Shag and Black Guillemot populations declined by 27% and 12%, respectively, between Seabird 2000 and Seabirds Count (2015-2021).
Since it was first detected in UK seabird populations in 2021, HPAI has had a devasting impact, killing tens of thousands of birds, particularly Great Skuas, Gannets, terns and gulls. There remains uncertainty regarding the scale of the population-level effects of HPAI on some seabird species, and further fieldwork has been carried out to help determine this. Furthermore, uncertainty persists regarding the long-term impacts of HPAI and the capacity for populations to recover. All species will be assessed again in BoCC6, currently scheduled for publication in 2027.
Although these results are alarming, it is vitally important that we remember that the UK remains internationally important for its breeding seabirds, and these need to be protected. Britain, Ireland, Isle of Man and Channel Islands supported the majority of the global population of Manx Shearwater (around 96%), Northern Gannet (estimated at 70%) and Great Skua (estimated at 64–67%), and a large proportion of the North Atlantic biogeographical populations (>30%) of another seven seabirds: Roseate Tern, European Storm-petrel, Shag, Common Guillemot, Razorbill, Lesser Black-backed Gull, and Herring Gull.
The UK seabird populations are exposed to a growing list of threats and pressures that include reduction in prey availability due to overfishing, incidental bycatch, non-native and native predators and offshore renewable energy development. In addition, there is the growing threat from climate change and the emergence of epi-zootic diseases such as HPAI across large geographical areas. These all raise concerns around the resilience of UK seabird populations. There is, however, cause for hope; for example, the UK and Scottish Governments decisions to close the Sandeel fisheries is a very significant positive step in the right direction, and although the European Union is challenging this curb on sandeel fishing, we believe such action is essential to support our struggling seabirds.
Other actions the RSPB would like to see include:
This study was a partnership project between the RSPB, British Trust for Ornithology, Game & Wildlife Conservation Trust and the government agencies - Joint Nature Conservation Committee, NatureScot, Natural England, Natural Resources Wales and Northern Ireland Environment Agency, and was funded by RSPB and Natural England as part of the ‘Action for Birds in England’ partnership.
Finally, we are extremely fortunate in the UK to have many thousands of dedicated volunteer birdwatchers, coordinated by professional research and conservation organisations, collecting information on UK bird populations. We would like to thank all those that have helped to monitor seabird population over the last five decades, without which such assessments would be impossible.
Table 1: BoCC5 addendum assessments for the 28 seabird species. Yellow-legged Gull was added to the species list in BoCC3. Leach’s Storm-petrel was added to the Red List in 2021.