Breeding Birds Survey Report 2023 Update

The BTO publishes a yearly Breeding Bird Survey report, which gives us the latest information on bird population estimates. The 29th annual report has just been published and it reviews population trends up until 2023. But what is the Breeding Birds Survey and what do the results show?

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The Breeding Birds Survey (BBS) was established in 1994 to collect data on our British bird species throughout the UK. Random 1km squares are selected across the UK and volunteers visit these locations in the morning twice between April and June (during the breeding season peak). Volunteers then record adult birds that they encounter whilst walking transects across their 1km square, including birds in flight, singing, and calling. In recent years, additional data on habitat type has also been collected. This data is then analysed to produce the annual BBS report and it keeps us up to date on trends and fluctuations in bird populations.

This year's report shows that 35 bird species (including some songbirds) have shown long-term increases in numbers between 1995 to 2022 in the UK, and 42 species are undergoing long term decreases in this same period. Some of the trends highlighted in the report include the loss of many of our aerial insectivores, including the non-songbird swift (-66%), along with swallows (-24%) and house martins (-44%). Flycatchers have also been badly affected, including the spotted flycatcher (see image below) and pied flycatcher (-59%). One of the theories as to why our beloved insectivores are undergoing such steep declines is the ongoing declines in our aerial insects. In the last 20 years UK insect populations have declined by over 60%, mirroring worldwide estimates that 40% of insect species are at risk of extinction. This is bad news for our insect-eating friends and the wider ecosystem.

Farmland species have also been highlighted as being in long-term decline, due to changes in agricultural practices, habitat loss and climate change. These species are suffering from a lack of available food as machinery has been modernised and pesticides have reduced the numbers of available insects and weeds on farmland. Yellowhammers have declined by 31% over 27 years, along with linnets by 23%, skylarks by 11% and greenfinches by 67%, all of whom are on the farmland bird indicator.

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Between 1995-2022:

In England, our top declining songbirds were willow tit (-90%), spotted flycatcher (-73%) and tree pipit (-69%).

In Scotland, our top declining songbirds were greenfinch (-71%), whinchat (-64%) and rook (-36%).

In Wales, our top declining songbirds were greenfinch (-79%), yellowhammer (-76%) and starling (-66%).

In Northern Ireland, our top declining songbirds were greenfinch (-81%), reed bunting (-36%) and skylark (-35%).

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However, it is not all doom and gloom, with this year's report also showcasing some steep increases between 1995 and 2022. Cetti's warbler topped the charts, with a 934% increase in the UK (see image below). The small warbler was only observed on two 1km survey squares back in 1994 but was recorded in 150 squares in 2023. Fantastic news!

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Check out the full report by Heywood et al. here and to find more information about the issues causing songbird decline click here.

The SBS Team

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If you are a scientist and would like to shine a light on your recent research covering songbirds here in the UK, then let us know! As a supporter of our charity, if you have ideas for blog posts you would like to see and topics you would like us to cover on #theSBSblog, please contact us at [email protected] or our Research and Engagement Manager at [email protected]. 

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