Storm-induced shifts in optimal nesting sites: a potential effect of climate change

Extreme storm events encountered during any stage of the annual cycle can result in increased mortality and influence population dynamics. Storms during the reproductive season, when birds are tied to fixed nesting locations, can be particularly problematic. Given predicted changes in the frequency and intensity of storms in a changing climate, studies examining the impacts of storms on reproductive success in model systems are important. Island-nesting seabirds may be particularly vulnerable to changes in storm frequency and intensity. Here, we report on the effects of an extreme storm in June 2012 on Herring Gull ( Larus argentatus ) reproduction on an island in the Gulf of Maine, USA. More than 22 % of monitored nests were lost in this single event leading to a seasonal shift in the optimal nesting locations for birds in our population. Nests closer to water and nests located at low elevations were disproportionately affected by the unusual weather, reversing trends in optimal nesting sites recorded in previous seasons. Spatiotemporal shifts in optimal nesting locations, therefore, may be one result of climate-induced changes in storm frequency and intensity. Although some birds with nests destroyed in the storm attempted to renest, these attempts experienced low success, and overall reproductive success in the storm-affected season was lower than in the previous three nesting seasons.