The majority of Scotland’s breeding bird species have shown a population increase over the past 30 years, according to a new report.
The latest official statistic report of 66 Scottish terrestrial breeding bird species by NatureScot shows increases for 36 of them between 1994 and 2023, with 23 species indicator results showing decline and seven remaining stable.
Woodland birds have seen the largest indicator increase of over 50%. Chiffchaff numbers have increased 1428% as well as great spotted woodpeckers by 699% and blackcap by 593%.
Despite being one of our commonest birds, chaffinches have recently declined by 13% in part due to the suspected presence of the bird parasite Trichomonas gallinae, which is linked to unhygienic bird feeding areas. Climate change, evidenced by milder winters, is also contributing to these declines.
A decline of 17% in Capercaillie has been linked to death from collisions with fences and potentially a negative effect of rising temperatures from climate change.
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However, upland birds have shown the largest declines (-20%). Long-term changes in upland bird populations have been contributed to by several factors, including climate change, forest expansion, and changes in site-based management practices such as grazing and predator control.
The report also shows that, since 1994, there has been an increase of 14% for urban bird species. The greatest long-term increases have been for jackdaw (+246%), magpie (+225%), goldfinch (+142%), woodpigeon (+134%) and great tit (+132%). There have been some substantial long-term decreases in other urban bird populations, however, including declines of more than 50% for greenfinch, swift and collared dove, and 25-50% declines for blackbird and starling. Possible drivers of these trends include changes in bird communities due to increased garden bird feeding, loss of green space and the impacts of diseases such as the aforementioned Trichomonas gallinae.
Swifts are experiencing a substantial long-term decline (-60%) which may be related to the reduced availability of suitable nesting sites on buildings, though a reduction in availability of flying insects may also play a role.
Scotland’s terrestrial breeding birds include familiar species such as chiffchaff, great tit, wren, song thrush, magpie, kestrel, greenfinch, lapwing, oystercatcher and skylark. They occupy a wide range of habitats including farmland, upland, woodland and urban areas.
Simon Foster, NatureScot Trends and Indicators Analyst said: “Since many bird populations are widespread and abundant, can respond quickly to environmental change, and are well surveyed in the UK through volunteer-based and professional surveys, they are useful biodiversity indicators. This report clearly shows that the emerging long-term differences in Scotland’s terrestrial breeding bird populations are dependent on a species’ ability to adapt to climate and habitat changes.
“Not only do we have our part to play in ensuring Scotland’s habitats are supported to function at the best of their potential for nature, but we can also make space for nature in our gardens by keeping feeding areas clean to help reduce the chance of diseases being passed within bird populations. Ensuring that sufficient food for only one to two days at a time is left in feeders, and that bird stations are regularly cleaned, is a great start.”
The full statistical publication can be accessed at Official Statistics: Scottish Terrestrial Breeding Birds 1994 – 2023.
