The decline in Scotland’s breeding seabird numbers may be slowing down, a new report suggests.
The latest biodiversity indicator published by Scottish Natural Heritage (SNH) uses data largely collected by volunteers to look at numbers of 11 species of breeding seabird.
The results show that, having declined by more than 30% from 1986 to 2011, population levels have since remained fairly stable.
Overall numbers have declined by an average of 32% since 1986. Only two of the species have maintained or increased in breeding numbers over the period (common gull and common tern).
Arctic skua, whose breeding stronghold is the Northern Isles, has experienced the largest decline of 78%. Their decline has been linked to changes in the availability of sandeels, which has also affected Northern Isles populations of kittiwakes and terns. Declines are also apparent for herring gull and great-black backed gulls across Scotland.
While below earlier levels, there are signs of some populations such as guillemot and black-legged kittiwake stabilising, with some colonies showing increases.
Common tern and Arctic tern numbers increased since the last report. Terns are known to be highly variable in breeding numbers and it is too early to say if this trend is going to continue.
Seabirds are not only vulnerable to changes in the seas around Scotland, many migrate across the Atlantic and technology is beginning to improve our understanding of their movements.