Effects of Spatial and Temporal Variation in Resource Availability on the Growth Rates and Survival of Dunlin (Calidris Alpina Hudsonia) Chicks

Long-distant migrants nesting in the Arctic experience condensed breeding seasons and shorter periods of high arthropod availability due to climate change. Shorebirds have precocial chicks which may compensate for food shortages by responding to spatial and temporal variation in arthropod availability. I hypothesize that shorebirds capitalize on this mobility to select quality foraging habitats to maximize chick growth and survival. I monitored arthropod biomass during chick rearing in Churchill, Manitoba and East Bay, Nunavut to document variation in habitat use, growth and survival in relation to variation in arthropod biomass. Movements of Dunlin (Calidris alpina hundsonia) chicks were observed from hatch until fledging to investigate whether chicks responded to resource hotspots. Dunlin chicks, however, did not significantly respond to hotspots of arthropod biomass. Despite potential asynchronies between chick rearing and food resources from climate change, flexibility of foraging behaviour among Arctic-breeding shorebirds may contribute to reducing vulnerabilities for other species.