Bird indicators are calculated annually, with the UK and England indicators produced jointly by the BTO and RSPB for Defra, and the Scottish indicators produced by the BTO for Scottish Natural Heritage. The indicators are based largely on data collected by volunteers contributing to national bird monitoring schemes such as the Breeding Bird Survey (BBS) and the Wetland Bird Survey (WeBS).
UK and England
The latest updates of the UK and England bird indicators based on population trends of wild birds were published on 7 November 2019. These indicators are part of the government’s suite of biodiversity indicators and show how the fortunes of birds of farmland, woodland, waterways and wetlands, and marine and coastal areas have fared between 1970 and 2018. Population trends of common birds that are native to, and breed in, the UK are assessed using two assessment periods: the long-term (for most species between 1970 and 2018) and the short-term (2012-17). The wintering bird indicator shows how the internationally-important numbers of wintering waders, wildfowl and other waterbirds using our coasts and in wetlands have changed since ca. 1975. The bird indicators are part of the government’s suite of biodiversity indicators and show how the fortunes of birds associated with different landscapes have fared.
- The breeding farmland bird index continued to fall and has declined by more than half between 1970 and 2018 in the UK. Whilst most of these declines occurred in the late 1970s and early 1980s, there was a short-term decline of 7% since 2011. Farmland specialists showed the most prominent declines; for example, Corn Bunting, Grey Partridge, Turtle Dove and Tree Sparrow all declined by at least 90% since 1970. Grey Partridge and Turtle Dove also declined strongly in the short-term, but there was no change for Corn Bunting or Tree Sparrow during this time. Conversely, some farmland specialists (e.g. Stock Dove and Goldfinch) have more than doubled in the long-term. This illustrates that responses to pressures are likely to vary between species.
- The breeding woodland bird index for the UK has declined by 30% between 1970 and 2018, and 5% over the recent short-term period. These declines are greater than documented previously, driven by the declining numbers of woodland specialists; down 46% since 1970. Generalist woodland species, typically those that also breed in gardens or wooded areas of farmland, have increased overall, by 14%. Woodland species such as Lesser Spotted Woodpecker, Spotted Flycatcher and Willow Tit have shown the most serious declines (more than 80%) since 1970, whilst numbers of Long-tailed Tit, Blackcap and Nuthatch have almost doubled, and the Great Spotted Woodpecker is three times as abundant as it was several decades ago.
- The breeding water and wetland bird index for the UK fell by 6% between 1975 and 2018, but over the short-term increased slightly by 3%. Over the long-term, species associated with slow-flowing and standing water, and with eedbeds, fared better than those associated with fast-flowing water or with wet grasslands. Lapwing, Redshank, Snipe and Common Sandpiper showed the strongest declines over the long-term, athough Snipe has shown a recovery of 27% in the recent short-term period.
- As with last year, the breeding seabird index has not been updated this year due to a shift of effort by the JNCC Seabird Monitoring team towards the ongoing Seabird Census. In the UK, the seabird index declined by 22% between 1986 and 2015. Declines began in the mid-2000s; and more recently, between 2009 and 2014 there was a 14% decline in the indicator, driven largely by large declines for Arctic Skua and Kittiwake.
- The wintering waterbird index was 106% higher than in 1975/76 in the UK. The index peaked in the late 1990s, and has been declining since; by 4% between 2010/11 and 2015/16. Some wintering waterbirds have increased markedly over the long-term, including Gadwall, Whooper Swan, Avocet and Black-tailed Godwit. Conversely, White-fronted Goose, Eider, Ringed Plover and Dunlin have declined.
The latest figures, released in November 2019, show a positive long-term trend for woodland birds in Scotland, with this group increasing by 58% between 1994 and 2018. Chiffchaff, Great Spotted Woodpecker, Blackcap, Great Tit, Bullfinch, Lesser Redpoll and Tree Pipit have all increased in abundance, some of which can be attributed to northward shifts in breeding range and changes in the extent of suitable habitat.
The indicator for farmland birds is also positive, with Goldfinch, Whitethroat and Reed Bunting among the species contributing to a 12% increase since 1994, albeit following declines in range among many farmland species since the 1970s revealed by the BTO's bird atlases.
Upland birds declined by 15% during the BBS period, populations of Dotterel, Curlew, Black Grouse, Common Sandpiper and Hooded Crow having decreased by more than 50%. Most of these species have been negatively affected by changes in land management or climate change which is also potentially linked to a northward shift in the centre of the Carrion Crow/Hooded Crow hybrid zone and consequent decline in Hooded Crows.
Many species exhibited a short-term decline between 2017 and 2018, probably as a result of the so-called 'Beast from the East'. These declines were most common among woodland residents, with Wren, Bullfinch, and Goldcrest the most strongly affected. Robin, Treecreeper, Great Spotted Woodpecker and Lesser Redpoll also declined, though to a lesser extent.
The latest Biodiversity Indicator for Wintering Waterbirds in Scotland was released by NatureScot in September 2021. This indicator tracks the population trends of 41 species, which are primarily counted by volunteers taking part in the BTO/RSPB/JNCC Wetland Bird Survey (WeBS), supplemented with additional targeted counts for geese and swans, and periodic surveys of rocky shore waders (the Non-Estuarine Waterbird Survey, NEWS).
This indicator showed that overall waterbird numbers have decreased by 7%. Much of this decline is explained by waders, with numbers for the 14 species monitored 58% lower than in winter 1975/76. There was more positive news for ducks and swans (16 species), which increased by 21%, and geese (seven species/populations), which rose in number by 274%.
Our programme of research in Scotland aims to better-understand the issues affecting our bird populations in order to inform future management. Current work programmes include collaborative research on breeding wader management and conservation, detailed studies of Short-eared Owl ecology and movements, and work to understand how woodland expansion and regeneration can impact bird populations.
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