Five seabird species are added to the Birds of Conservation Concern Red List in this addendum to the 2021 update, bringing the total number of Red-listed seabird species to 10, up from six since seabirds were last assessed. The Amber List of seabirds moves from 19 to 14 species, and the Green List increases from one to two species.

A study led by BTO uses data from GPS tracking and other research to identify the likelihood of seabirds of 27 species interacting with areas off sea earmarked for 41 new offshore wind farms around the UK.

The report includes detailed information about the population trends and breeding success of seabirds in Northern Ireland, over the 2023 breeding season. Notably, Fulmar and Kittiwake populations are reported to be experiencing continued declines, while Guillemot, Common Gull and Herring Gull populations show increases at most breeding sites. Low productivity was reported in Black-headed Gulls, Sandwich Terns and Common Terns, likely due to the impacts of highly pathogenic avian influenza (HPAI). Although Black-headed Gulls make up the majority of confirmed HPAI mortality cases in Northern Ireland in 2023, other birds significantly affected include terns, Kittiwakes and auks. A contributor report about HPAI in Northern Ireland by Ronan Owens (Higher Scientific Officer, DAERA, NIEA) details developments in environmental organisations’ responses to HPAI in 2023, including cross-sector communication, improved surveillance and monitoring of HPAI impacts, and improved online systems for the public to report dead birds. Monitoring reports for Strangford Lough and the Outer Ards are included, as well as several additional contributor articles: Copeland gull censuses, by Roisin Kearney (Assistant Conservation Officer, RSPB). The Copeland Islands host one of the largest mixed gull colonies in Northern Ireland, with significant numbers of Lesser Black-backed Gulls and Herring Gulls. The annual gull census was established in 2018; the article details the refinement of the methodology to date as well as the census results so far. Manx Shearwater tracking, by Patrick Lewin (DPhil Student, OxNav, Dept. of Biology, University of Oxford). Tracking the Manx Shearwaters that breed on Lighthouse Island (one of the three Copeland Islands) began in 2007. The article describes the history of tracking Manx Shearwaters from Copeland, including recent advances in technology that have allowed the tracking of fledgling birds as well as adults of breeding age, and the impact of this research on the conservation of shearwaters. Puffin surveys on Rathlin, by Ric Else (Life RAFT Senior Research Assistant, RSPB). Rathlin Island hosts Northern Ireland’s largest seabird colony. The response of seabirds to the removal of introduced Ferrets and Brown Rats from Rathlin is currently being monitored, with a particular focus on Puffins. These birds are especially vulnerable to mammalian predators because of their burrow nests. The article describes the challenges associated with calculating a population estimate, monitoring productivity and mapping the distribution of this species, and how these are being addressed in seabird surveys on Rathlin.

High pathogencity avian influenza hitting seabird colonies and severe marine heatwaves disrupting marine food webs highlight just two of the many threats that seabirds must contend with. This BTO study examines the information needed to come up wtih effective conservation measures for seabird species.

The latest review of the conservation status of birds in Wales. The report assessed all 220 bird species which regularly occur in Wales. There are now 60 species of bird on the Red List, with 91 on the Amber List and just 69 - less than a third of the total number of species - on the Green List. The latest review of the conservation status of birds in Wales comes 20 years after the first, when the Red List was less than half the length it is today. The report assessed all 220 bird species which regularly occur in Wales. There are now 60 species of bird on the Red List in Wales, with 91 on the Amber List and 69 on the Green List. The Birds of Conservation Concern in Wales report assesses the status of each species against a set of objective criteria. Data sources include the BTO/JNCC/RSPB Breeding Bird Survey and the BTO/RSPB/JNCC Wetland Bird Survey, as well as Bird Atlases and other BTO-led monitoring schemes and citizen science initiatives. These are used to quantify the changing status of the species’ Welsh population. The UK, European and global conservation status of the species is also considered, placing the Welsh population into a wider context. The Red ListSwift, Greenfinch and Rook – familiar breeding species in steep decline across the UK – are among the new additions to the Welsh Red List, which now also includes Purple Sandpiper, on account of a rapidly shrinking Welsh wintering population, and Leach’s Petrel, an enigmatic seabird in decline across its global range. These species now sit alongside well-known conservation priorities, such as Curlew, Hen Harrier and Turtle Dove as birds at risk of being lost from Wales for good. Uplands and woodlands Many of the species on the Red List are found in upland and farmland habitats. Starling, Tree Sparrow, Yellow Wagtail and Yellowhammer can no longer be found in much of Wales, while iconic species of mountain and moorland, such as Ring Ouzel, Merlin and Black Grouse, remain in serious trouble. Wales is well known for its populations of woodland birds; however, many of these – including Lesser Spotted Woodpecker, Willow Warbler and Spotted Flycatcher – also feature on the Red List. Goldcrest, which has seen its Welsh population shrink alarmingly in recent decades, is another new addition. On the coast The assessment for Birds of Conservation Concern Wales 4 took place before the impacts of avian influenza could be taken into account. Breeding seabird species have been struggling in Wales for many years, however, and most were already of conservation concern before the outbreak of this disease. Kittiwake, Puffin, Black-headed Gull, and Common, Arctic and Sandwich Tern remain on the Red List. Wales holds internationally significant numbers of breeding seabirds, making the decline of these colonies a global concern. The Amber ListDeclines in Wheatear, Garden Warbler and House Martin - all migrants which breed in Europe and winter in sub-Saharan Africa - mean these species have moved from the Green List to the Amber List. Many other ‘Afro-Palearctic' migrant species are also in decline, but the potential reasons for this, such as habitat loss and reduced availability of invertebrate prey, are not well understood. Closer to home, the declines in the Welsh Chaffinch population, linked to the disease trichomonosis, have seen the species Amber-listed. A number of other species have been placed on the Amber List because of the wider importance of their Welsh populations, which in each case make up more than half the UK total. Wales is home to more than three-quarters of the UK’s Choughs, for example, so recent declines are cause for concern. The nation’s breeding populations of Manx Shearwater, Pied Flycatcher, Goshawk and Hawfinch also account for more than half the UK total, as does its wintering population of Spotted Redshank. It’s not all bad news, though: some species now on the Amber List have moved up from the Red List, indicating some positive change in their population trends. These include Common Sandpiper, Great Black-backed Gull, Bullfinch, Goldcrest and Pied Flycatcher. The Green ListWhile the report contains much cause for alarm, several conservation success stories shine through. Red Kite was almost lost as a British bird during the first half of the 20th century, when only a handful of pairs remained in remote Welsh valleys. Since then, a sustained conservation effort has brought the species back from the brink. Wales is now home to more than 2,500 pairs of Red Kite and the species has now been moved to the Green List, reflecting this incredible change in fortunes. Song Thrush, Reed Bunting, Long-tailed Tit, Redwing and Kingfisher are among the other species to have gone Green, providing much-needed hope that things can go up as well as down.

New research involving BTO has developed a framework to identify how wildlife might be affected by renewable energy developments. Over the past century, an accelerating pace of industrialisation has led to increasing numbers of manmade structures, including renewable energy developments (such as wind turbines) that extend into and co-occupy the airspace of birds and other airborne wildlife. In order to understand how wildlife might be affected by these structures, we need data that describes species flight characteristics, such as how high and fast they fly. However, the methods used for this data collection are often based on legislation and guidance which has not been updated for some time, and therefore does not make best use of tools and technologies currently available. In the case of bird flight heights, measurements are often based on estimates from visual observers, whilst information on flight speeds are often derived from published literature. Such data are likely to be less accurate and less representative than data collected from technologies like radar or GPS telemetry, and in turn contribute to less accurate and less representative estimates of the potential impacts of renewable energy developments. A key reason that these visual- and literature-based data collection methods have persisted may be the lack of a comprehensive understanding regarding the tools and technologies that currently exist, and how these can be applied to the collection of bird flight data in a systematic and consistent way. In order to assess the tools and technologies available, BTO scientists collaborated with colleagues at the University of the Highlands and Islands and the RSPB to carry out a systematic literature search. For each method identified, the authors considered what kind of data could collect be collected (e.g. flight characteristics, longevity of data collection), how these data were collected (e.g. via GPS devices attached to birds) and if there was any evidence that the measurements from each tool had been or could be verified through calibration or validation. Based on the results of this search, the authors developed a framework, setting out how the tools available could be used during baseline ornithological data collection as part of Environmental Impact Assessments (EIAs), which help to establish whether a renewable energy development should go ahead. This work removed some of the uncertainty around the use of the tools that are currently used. This framework can be incorporated into EIA legislation and offers guidance about the collection of bird flight data, making the best use of the technology available to ensure that decisions about which renewable energy developments receive permission to be built are based on the most accurate and representative data possible.

The UK has lost seven species of breeding birds in the last 200 years. Conservation efforts to prevent this from happening to other species, both in the UK and around the world, are guided by species’ priorities lists, which are often informed by data on range, population size and the degree of decline or increase in numbers. These are the sorts of data that BTO collects through its core surveys. For most taxonomic groups the priority list is provided by the International Union for Conservation of Nature (IUCN) – the IUCN Red List comprises roughly 12,000 species worldwide and their conservation status. However, for birds in the UK, most policy makers refer to the Birds of Conservation Concern (BoCC) list, updated every six years (most recently in 2015). A new study funded by the RSPB and Natural England in cooperation with BTO, WWT, JNCC, and Game & Wildlife Trust has carried out the first IUCN assessment for birds in Great Britain. The study applied the IUCN criteria to existing bird population data obtained from datasets like the BTO/JNCC/RSPB Breeding Bird Survey (BBS). The criteria take into account various factors, most notably any reduction in the size (both in abundance and range) of populations, loss of habitats key to the species, small or vulnerable population sizes, and extinction risk. Alongside this, the criteria look to see if there is a “rescue” effect – such as immigration from neighbouring populations that might boost the population’s numbers, reducing the risk of extinction. The species are then categorised into one of the threat levels below. The results of the new study show that a concerning 43% of regularly occurring species in Great Britain are classed as Threatened, with another 10% classified as Near Threatened. Twenty-three breeding or non-breeding populations of birds were classed as Critically Endangered, including Fieldfare and Golden Oriole (both possibly extinct as breeders), Whimbrel, Turtle Dove, Arctic Skua and Kittiwake, as well as non-breeding populations of Bewick’s Swan, White-fronted Goose and Smew., Over the past 200 years, seven species have gone extinct as breeders in Britain, including Serin, Temminck’s Stint and Wryneck in the past 25 years. The total percentage of threatened birds in Great Britain (43%) is high compared to that seen elsewhere in Europe (13%). Reasons for this are not entirely clear, although it may be that Britain’s island status has something to do with this, as there are fewer neighbouring “rescue” populations. Although the results from the IUCN assessment and BoCC assessment largely overlap, the IUCN assessment raises the level of concern for species such as Red-Breasted Merganser, Great Crested Grebe, Moorhen, Red-Billed Chough (all classed as Vulnerable), and Greenfinch (Endangered). These species might thus warrant closer monitoring in the near future. In contrast, the BoCC assessment identifies a number of species of concern whose declines have been more gradual but over long time periods (e.g. Skylark and House Sparrow). The authors emphasise that this assessment is not a replacement of the BoCC report, but rather that the two reports complement each other. With this new wealth of knowledge, there will hopefully be even more support for those species that need it most.

Report of work carried out by the British Trust for Ornithology in collaboration with the Environmental Research Institute on behalf of the Marine Scotland Science. Accurately estimating birds’ risk of collision with offshore wind turbines is a key part of the decision-making process for proposed renewable developments. However, the evidence base for quantifying the number of birds likely to avoid colliding with turbines is limited. Recent BTO-led work helping to fill this gap, improving the understanding of the impacts of offshore renewables on marine wildlife.