SI2015-C-4: “The status, ecology, and conservation of Sable Island’s seabirds” – Robert A. Ronconi

Sable Island is the most isolated seabird colony site in eastern Canada, offering a unique opportunity to study the ecology and population dynamics of terns and gulls in an area removed from the influences of many coastal human activities.  In this presentation I will summarize some of the key results from recent and historical research that has been conducted on Sable Island’s tern and gull populations.  Historically, the island was thought to harbour one of the largest aggregations of breeding terns in the North Atlantic, suggesting that it was once a globally significant breeding colony.  Though the tern population declined dramatically sometime around the 1940s, trends over the past 50 years suggest that the tern population is recovering while gull populations have been gradually declining.  Collections of Herring Gull eggs have revealed contaminant concentrations that are higher on Sable Island than at many other colonies across Canada.  Dietary analysis suggests prey partitioning among tern and gull species, and changes in gull diets over the past 40 years.  Finally, tracking studies of gulls are revealing individual specialization in foraging tactics including round-trips of more than 100 km, associations with offshore natural gas platforms, and year-round use of Sable Island.  Together these research projects highlight some of the unique aspects of the ecology of terns and gulls that breed on Sable Island.