Majority of Scotland’s breeding bird species show population increase

Woodland birds have seen the largest indicator increase of over 50%. Chiffchaff numbers have increased 1428% - most probably driven by increasing temperatures – as well as great spotted woodpeckers by 699% and blackcap by 593%. 

Chaffinches are one of our commonest birds, and a regular species in gardens and woodland, but they 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.

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. Curlew breeding numbers have declined over 60%, and changes to land management, climate and food availability are all having an impact. Targeted action is taking place in Scotland to help restore suitable breeding habitats and research is underway to help improve our understanding of the declines.

Since 1994, there has been an increase of 14% for urban bird species. This is largely due to an increase until the mid-2000s, which was followed by a slow decline. 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. Swifts are long-distance migrants and there may also be factors that influence their survival outside the breeding season during migration or on their wintering grounds. Action to create nesting sites is underway in some of our cities.

Between 1994 and 2023, there has been a long-term increase of 7% among the species trends that contribute to the farmland bird indicator. This increase was largely due to positive population trends in areas dominated by pastoral farmland, where the index increased by 22%. Farmland waders (oystercatcher and lapwing) have seen the largest declines, and these have been linked to changes in farming practices. However, there are considerable efforts to reverse the trends for breeding waders across Scotland through projects such as Working for Waders.

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. Some species show a strong preference for a particular habitat, for example coal tit is a typical woodland bird. Others use a wider range of habitats. Skylark occupies lowland arable land as well as farmed and semi-natural upland areas. Great tit is a familiar species of woodland but also occupies the woodland and hedgerow components of farmland and gardens. 

Trends differ between species and may be due to factors within the breeding areas in Scotland or, for migratory birds such as whitethroat trends can be influenced by conditions on migration routes or wintering areas. Climate change is clearly affecting some bird populations with evidence of birds shifting northwards (e.g. willow warbler). 

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.”