Monitoring Canadian Arctic seabirds at the Prince Leopold Island Field Station, 1975-2023

The research station at Prince Leopold Island (PLI), initiated in 1975, was the first seabird monitoring site created in the Canadian Arctic. The island supports 150 000 breeding pairs of seabirds, principally thick-billed murres (Uria lomvia), black-legged kittiwakes (Rissa tridactyla) and northern fulmars (Fulmarus glacialis), along with ~70 pairs of glaucous gulls (Larus hyperboreus) and several thousand black guillemots (Cepphus grylle). Baseline observations of seabird breeding biology were made during 1975-77. Subsequent monitoring has taken place in 22 of the 47 seasons, with work during 2001-2003 replicating the original baseline studies. Population trends of breeding seabirds have shown kittiwakes (sharply) and murres (gradually) increasing, while gulls (definitely) and fulmars (likely) have declined. The most striking scientific findings from PLI were related to the effect of annual ice break-up on seabird phenology, clutch size, and reproductive success. For contaminant research, PLI has become one of the core monitoring sites in Canada and internationally, documenting dramatic changes in concentrations of various contaminants in the Arctic marine environment. Given the international impact of research and monitoring at PLI for almost five decades, the continuation of seabird research at PLI, the most important seabird colony in the Canadian Arctic, is essential.