Seabird foraging ranges as a preliminary tool for identifying candidate Marine Protected Areas

Abstract

There is a growing need to identify Marine Protected Areas (MPAs) for marine species. For seabirds, MPAs include those near breeding colonies, offshore foraging areas, inshore habitats for wintering species, and migratory bottlenecks. However, frequently there is a lack of readily available current and comprehensive data on foraging areas used by species from particular colonies. Therefore, representative breeding season foraging ranges for each species may be useful alongside other datasets for scoping candidate MPAs. We reviewed studies that estimated foraging range for 25 species of UK breeding seabirds. For representative foraging ranges, we prioritised studies, giving highest value to those based on direct tracking of birds (21%); then those involving indirect estimates using flight speeds and time activity (12%) followed by, boat, aerial, and land-based ‘survey’ observations (46%); and finally we gave lowest value to speculative estimates (21%). Highest confidence was placed in the foraging ranges of northern gannet (Morus bassanus), black-legged kittiwake (Rissa tridactyla), and common guillemot (Uria aalge), and lowest for common gull (Larus canus), common eider (Somateria mollissima), Leach’s (Oceanodroma leucorhoa) and European storm petrels (Hydrobates pelagicus). Both annual and colony-specific variation was evident for some species. Manx shearwater (Puffinus puffinus), northern gannet, and northern fulmar (Fulmarus glacialis), had the largest foraging ranges (maximum ranges >330, 590 and 580km, respectively), whereas red-throated diver (Gavia stellata) and little tern (Sternula albifrons) had the smallest (maximum ranges 9 and 11km, respectively). Representative foraging ranges may be useful to suggest likely colony-specific foraging areas, prior to habitat-association modelling for defining candidate MPAs. The approach here has international applicability, and would help progress towards more comprehensive protection of seabird populations.