At-Sea Turnover of Breeding Seabirds: Final Report to Marine Scotland Science

Scottish Marine and Freshwater Science Vol 6 No 10

The aim of this project was to review the potential issue of "turnover‟ of individual seabirds at sea during the breeding season and to assess how this may lead abundance estimates derived from boat or aerial surveys to underestimate the total number of birds that use an area during the course of the breeding season. Turnover rates in species for which sufficient data were available are estimated.

This project provides relevant information to assist Marine Scotland Science with identifying knowledge gaps that may benefit from further data collection. It will also enable Marine Scotland Licensing Operations Team and Marine Renewables Developers to make more informed assessments of the potential impacts of development projects as part of the required environmental evaluations. The project, therefore, has significant strategic relevance for site characterisation and monitoring in Scotland and beyond. Turnover is clearly only one factor that will need to be considered when assessing the risks to seabird populations from offshore developments. A related task will involve quantifying the fate of birds that lie within the development footprint. Further work is needed in order to understand whether higher levels of turnover lead, all else being equal, to higher or lower estimates of development-related mortality.