Early signs of recovery for Scotland’s seabirds

Seabird numbers in Scotland have been falling since the early 1990s and by 2015 the number of seabirds breeding around our coasts was half of the 1986 level, when the UK Seabird Monitoring Programme (SMP) first started. However, 2015 was a relatively successful year for producing chicks. The latest report shows that the decline has slowed and numbers may have stabilised over the past four years.

SNH is working on several projects to help combat some of the pressures on seabirds. These include identifying Special Protection Areas (SPAs) to protect important foraging and breeding sites for birds, and the control of predators, such as brown rats and American mink, along our coast and on our islands.

SNH publishes an annual Biodiversity Indicator for seabirds, prepared using data from the SMP – a partnership project, co-ordinated by the Joint Nature Conservation Committee and involving a range of conservation partners, including SNH. Twenty-four species of seabird regularly breed in Scotland and the indicator assesses breeding numbers for 12 species, and breeding success for 12 species.

Out of the 12 species assessed for breeding numbers in 2015, common guillemot, common tern, Arctic tern and Sandwich tern have each shown a slight increase since 2011. Arctic skua has suffered the worst declines, with numbers down 76% since 1986. The breeding stronghold for this species is the Northern Isles, where there has been a fall in the availability of sandeels, which the Arctic skuas get by chasing other species until they drop their catch. Increased predation by great skua has also been linked to their decline.

Simon Foster, SNH’s trends analyst, said: “Scotland is an incredibly important place in the world for seabirds. Our seas and marine wildlife are a unique and exciting part of nature and they attract many thousands of people to visit Scotland every year. This latest indicator shows the importance of continued long-term monitoring in helping understand what is happening to our seabird populations.

Seabirds are also important indicators for assessing the state of the marine environment. Seabirds respond to a range of factors, such as food availability, climate, predation and pollution, all of which are thought to be contributing to the current decline. Crucially, although they rely on the sea, they breed on land and so are relatively easy to monitor, compared with other marine life.

Scotland’s Biodiversity Indicators are a key aspect of the 2020 Challenge for Scotland’s Biodiversity – and have been developed to monitor changes in our nature and landscapes. They provide evidence of progress towards policy objectives and demonstrate what is actually happening.

In 2015, breeding success (the number of chicks produced) was higher than the long-term (1986 to 2014) average for half of the 12 species assessed: Arctic skua; black-legged kittiwake; common tern; common guillemot; northern gannet; and Sandwich tern. A recent survey of northern gannet has shown a large increase in their breeding numbers. Good breeding success and improved survival of immature and adult birds has helped boost populations and led to an expansion of their range.

Breeding success was lower than the long-term average for herring gull, little tern and Sandwich tern, while Arctic tern, puffin and great skua had breeding success around the long-term average.

On behalf of the Scottish Government, SNH has this year managed formal public consultations on a suite of 15 proposed Special Protection Areas (pSPAs) for marine birds. The sites are spread around Scotland’s coasts and islands and are designed to help a wide range of seabirds and other bird species which depend on our seas.

If designated, the sites will form part of Scotland’s network of Marine Protected Areas (MPAs), which covers approximately 20% of our seas. Developing a network of well-managed MPAs is one way the Scottish Government aims to meet its 2020 Biodiversity Challenge outcome of ‘clean, healthy, safe, productive and biologically diverse’ coasts and seas.

The full seabird indicator report is available on the SNH website. The indicator is part of a suite of biodiversity indicators which are used to assess the state of Scotland’s biodiversity.