Birds of Conservation Concern 5

The British Trust for Ornithology (BTO) has published the fifth edition of Birds of Conservation Concern.

Commonly referred to as the UK Red List for birds, the status of birds has now been reviewed five times, Covering the UK, Channel Islands and Isle of Man. The latest review was published this month, as Birds of Conservation Concern 5 (BOCC5).

This updates the last assessment in 2015. Using standardised criteria, experts from a range of bird NGOs, including BTO, assessed 245 species with breeding, passage or wintering populations in the UK and assigned each to the Red, Amber or Green Lists of conservation concern.

The bad news

This update shows that the UK’s bird species are increasingly at risk, with the Red List growing from 67 to 70. By contrast, the first Red List, published in 1996, had only 36 species. Eleven species have been Red-listed for the first time in 2021, six due to worsening declines in breeding populations (Greenfinch, Swift, House Martin, Ptarmigan, Purple Sandpiper and Montagu’s Harrier), four due to worsening declines in non-breeding wintering populations (Bewick’s  Swan, Goldeneye, Smew and Dunlin) and one (Leach’s Storm-petrel) because it is assessed according to IUCN criteria as Globally Vulnerable, and due to evidence of severe declines since 2000 based on new surveys on St Kilda, which holds more than 90% of the UK’s populations. The evidence for the changes in the other species come from the UK’s key monitoring schemes such as BTO/JNCC/RSPB Breeding Bird Survey (BBS) for terrestrial birds, the BTO/RSPB/JNCC Wetland Bird Survey (WeBS) for wintering populations and the Rare Breeding Bird Panel (RBBP) for scarce breeding species such as Purple Sandpiper.

Two species moved directly from the Green to Red List: Greenfinch and Ptarmigan. Increasingly severe declines in Greenfinch numbers have been reported in BBS reports for more than a decade, and the initial regional pattern of declines was associated with outbreaks of the disease Trichomonosis. This disease of the digestive tract is widespread in Greenfinch populations across Europe and may also be starting to affect other species such as Collared Dove, Sparrowhawk and Chaffinch. A species of montane uplands, Ptarmigan is a difficult species to census and data are scarce, but an analysis of game bag data for this quarry species revealed a long-term decline of more than 80% since the 1960s, in agreement with the loss of range revealed by Bird Atlas 2007-11 and the sensitivity to climate change of this montane species

The IUCN assessment resulted in 108 (46%) of regularly occurring species being assessed as threatened with extinction in Great Britain, meaning that their population status was classed as Critically Endangered, Endangered, or Vulnerable, as opposed to Near Threatened or of Least Concern. Of those 108 species, 21 were considered Critically Endangered, 41 Endangered and 46 Vulnerable. There is considerable overlap between the lists but unlike the Red List in BOCC5, IUCN2 highlights the vulnerability of some stable but small and hence vulnerable populations as well as declines in species over much shorter recent time periods, as seen for Chaffinch and Swallow.

Unlike previous BOCC assessments, where there was a clearer pattern of influx to the Red List, with upland and woodland species joining the already listed farmland species, this update is more of a mixed bag. However, the worsening status of Afro-Palearctic migrants continues with two aerial insectivores – Swift and House Martin – joining other migrants such as Cuckoo and Nightingale on the Red List. Although deteriorating conditions on the wintering grounds and on stopover sites are likely factors, the reliance of many long-distance migrants on insects and other invertebrates suggests that declines in those could also play a role.

The other group joining the Red List also encompasses migrants, in this case, wintering wildfowl and waders that breed at higher latitudes and to the east, but winter in the UK. Climate change and milder winters in regions such as the Baltic Sea have resulted in many of these species being less likely to migrate as far west and south as the UK, in a pattern termed ‘short-stopping’. This is likely the case for Red List newcomers Dunlin and Smew, but can be further complicated by broader declines in populations, as is known for the Eastern flyway populations of Bewick’s Swan.

The good news

There is also better news. In addition to White-tailed Eagle, which no longer qualifies for ‘historical decline’ thanks to further recovery of the breeding population and intense conservation efforts, five previously Red-listed species (Pied Flycatcher, Song Thrush, Black Redstart, Grey Wagtail and Redwing) have shown modest but sufficient improvements in breeding population status to have moved from Red to Amber.

Red Grouse, Mute Swan and Kingfisher also move from the Amber to Green. Overall, the Amber List has increased from 96 in BOCC4 to 103 in BOCC5, this difference reflecting both negative (moves to the Red List) and positive changes (moves to the Green List). The Green list, now 72 species long, includes a range of common garden species such as Blue Tit, Blackbird and Robin, and saw a net loss of nine species since BOCC4. Mute Swan and Kingfisher will have both greatly benefitted from ecological restoration and habitat creation projects involving wetlands, which are occurring up and down the UK currently. Red Grouse are thriving on managed grouse moors which dominate large areas of the uplands. Its worth noting that, of the native resident partridge and grouse species, Red Grouse is the only one on the green list. The others are all on the red list.

So what next?

The BOCC5 shows the usual culprits – development, climate change, agricultural practice, pollution and invasive species – for the declines. It is indicative of the ongoing biodiversity crisis, which is exacerbated by the climate emergency.

If we are to reverse these declines we must ensure that policies across the UK – including agricultural reform, net gain for biodiversity, the Environment Act in England – are delivered in meaningful and lasting ways. This means we need more professionals in the sector, from a broad range of backgrounds, and working to the highest standards. CIEEM continues to work on improving the diversity and inclusivity in the sector, and to provide Continuing Professional Development opportunities to improve skills and competence. We also continue to use our influence in our liaison with governments and agencies.

At the global scale it shows the importance of international cooperation and the need for a strong Global Biodiversity Framework to come out of Biodiversity COP15 which is currently planned for April-May 2022 in China. CIEEM is engaging with the Climate and Biodiversity COPs.