Breeding Bird Survey reaches 30-year milestone

The Breeding Bird Survey (BBS) celebrates its 30th anniversary this year, with the results from the latest survey demonstrating a picture of ups and downs for the UK's bird species.

BBS is the main scheme for monitoring the population changes of the UK's common and widespread breeding birds, producing population trends for 119 species.

The report reveals some extraordinary contrasts in fortune among UK's most familiar birds. Between 1995 and 2022, species such as Little Egret (up 2,347%), Red Kite (2,232%) and Cetti's Warbler (934%) have represented great success stories. However, the situation is quite the opposite for many others, with severe declines in the likes of Willow Tit (down 90%), Wood Warbler (81%) and Common Swift (66%), all which are struggling to cope in a contemporary UK.

Red Kite has been one of the UK's great conservation success stories of the past few decades (Geoff Snowball).

 

Volunteer-led survey

For 30 years, a total of almost 9,000 skilled enthusiasts have been contributing essential data to BBS, which is one of the UK's longest-running citizen science initiatives. BBS is a partnership project organised by British Trust for Ornithology (BTO), the Joint Nature Conservation Committee (JNCC) and the Royal Society for the Protection of Birds (RSPB).

With around 3,000 volunteers taking part in any given spring and summer, collectively the nations' birders have provided nearly 8 million records since BBS was launched in 1994, allowing scientists to identify any notable changes in the status of our breeding birds. Amazingly, at least 100 of these keen-eyed contributors have been submitting their observations for the entire three decades that the survey has been running. Around 7,000 individual sites across the UK have been covered at least once in this time, the survey having grown from around 1,500 sites in its first year to around 4,000 each year for the last seven years.

The BBS, following on from its predecessor, the Common Birds Census, gathers information from across the UK and helps paint a clear picture of just how well, or not, the UK's common and widespread land-based birds are faring. By analysing the collected data, scientists can see that while some birds such as Goldfinch, Great Spotted Woodpecker and Eurasian Nuthatch are doing reasonably well, others including Eurasian Curlew and Northern Lapwing are in steep decline.

Some species are faring differently in different parts of the UK. For example, Tree Sparrow and Willow Warbler are both doing well in Scotland but not in England. The reasons for these population changes are varied and the survey data allows scientists to investigate the potential drivers of change for each species. In all, the information from BBS helps to set bird conservation priorities in the UK, including Red Listing, contributing to Indicators and measuring nature recovery.

Tree Sparrow is faring well in Scotland but simultaneously struggling in England (Tom Moodie).

 

The factors driving change

Since the start of BBS, the data has shown that two-thirds of Common Swifts have disappeared from UK skies since 1995. The situation isn't much better for Swallow, with numbers having dropped by almost half in the last 10 years. For birds such as these, which rely heavily on aerial insects, any decline in these invertebrates means that there is simply less food for adult birds and their growing chicks. A reduction of breeding sites can be mitigated by the provision of artificial nesting sites, but the issue of diminishing food resources is much more difficult to resolve. These birds are not alone: of the 119 species monitored by BBS in the UK, 42 have decreased since 1995, while 35 have increased.

European Turtle Dove shows the greatest decline of all species, with numbers having plummeted by a staggering 97% since 1995%. It is now so rare that BBS cannot monitor it effectively, although the current hunting moratorium in Western Europe is giving cause for optimism that efforts to improve breeding habitats in England will support recovery.

Other farmland birds, such as Grey Partridge (down 62% since 1995) and Yellowhammer (31%), are in a similar predicament, although well-evidenced and well-targeted agri-environment measures can play a critical role in stemming the declines of these and other farmland species.

Intriguingly, a fifth of the species showing increases are non-native birds, with the big winners including Ring-necked Parakeet (up 2,154% since 1995) and Egyptian Goose (1,835%).

Non-native birds are among the big winners, with the UK Ring-necked Parakeet population up by 2,154% since 1995 (Irene Harrison).

 

What the experts say

Dr James Heywood, BBS National Organiser, said: "The sheer volume of information that allows us to see the high and lows of our breeding birds is all volunteer gathered. Without the dedication of the UK's BBS surveyors, we would not be able to see the changing fortunes of our bird populations, and with it look to identify causes and potential solutions. The report highlights declines in wide ranging groups of species, from birds reliant on insects, farmland and woodland birds, as well as pointing to additional and acute challenges like avian flu."

Simon Wotton, RSPB Senior Conservation Science, added: "The Breeding Bird Survey provides us with invaluable information about the state of our bird populations. By looking at this valuable long-term data we can see which species most need our help and where our efforts are best spent when addressing the nature and climate emergency. The changes in range and abundance of some of our bird species should give us cause for concern, and impetus for action."

Dr Paul Woodcock, Joint Nature Conservation Committee, commented: "Long-standing monitoring schemes, such as the Breeding Bird Survey, are critical to better understand the status of our natural environment and the pressures faced by our wildlife. Thanks to the collaborative effort of thousands of volunteers we have an invaluable dataset that informs policy, targets conservation action and evaluates success, as evidenced by the Red Kite recovery and by our understanding of which species are experiencing large declines."