Data from: 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 impact on the quality and/or quantity of cached food available to Canada jays. Future increases in such events, caused by climate change, could pose a serious threat to Canada jays and other food caching species that store perishable foods for long periods of time.

已有研究证实，分布范围边缘的种群极易受到气候变化的影响，但目前鲜有研究揭示驱动种群数量下降的具体机制。长期储存易腐食物的物种可能对环境变化尤为敏感，因为气候条件的改变会加速其贮藏食物的自然降解进程。本研究依托位于加拿大安大略省阿尔贡金省立公园的加拿大松鸦（Canada jay，Perisoreus canadensis）标记种群长达40年的繁殖监测数据——该种群处于加拿大松鸦分布范围的南部边缘——探究繁殖前期的气候条件是否会产生延续效应，进而影响繁殖成效。研究发现，秋季冻融事件的发生次数与加拿大松鸦后续晚冬季繁殖季的繁殖成效（窝雏数、巢成功率及雏鸟体况）呈显著负相关。本研究结果表明，冻融事件会对加拿大松鸦可获取的贮藏食物的质量和/或数量造成显著负面影响。未来由气候变化引发的冻融事件频次增加，可能会对加拿大松鸦及其他长期贮藏易腐食物的贮食物种构成严重生存威胁。