Autumn freeze-thaw events carry over to depress late-winter reproductive performance in Canada Jays

Evidence suggests that range-edge populations are highly vulnerable to the impacts of climate change but few studies have examined the specific mechanisms that are driving observed declines. Species that store perishable food for extended periods of time may be particularly susceptible to environmental change because shifts in climatic conditions could accelerate the natural degradation of their cached food. Here, we use 40 years of breeding data from a marked population of Canada jays (Perisoreus canadensis) located at the southern edge of their range in Algonquin Provincial Park, Ontario, to examine whether climatic conditions prior to breeding carry over to influence reproductive performance. We found that the number of fall freeze-thaw events was negatively correlated with reproductive performance (brood size, nest success, and nestling condition) in the subsequent late-winter breeding season of the Canada jay. Our results suggest that freeze-thaw events have a significant negative ...