Abstract

The Sandwich Tern Sterna sandvicensis is a familiar seabird yet little is known about its foraging ecology. This paper brings together the results from four years of boat-based visual tracking of Sandwich Terns from the UK’s largest breeding colonies, at Blakeney Point and Scolt Head, within the North Norfolk Coast SPA. Sandwich Tern is something of a ‘super tern’, capable of ranging more than 50 km from the colony at an average speed of 32 km/h and a median height of 25–30 m in a search for patchily distributed prey, which is typically captured by plunge diving with full immersion. Birds generally foraged alone but concentrated at ‘hotspots’, including those created by predatory fish, auks or marine mammals pursuing schooling ‘bait fish’ to the surface. Adults generally consumed small prey (<3 cm in length) but selected and carried larger clupeids or sandeels (up to 25 cm) to provision chicks. Our work has contributed to conservation planning for Sandwich Terns.