Experimental evidence and over forty years of monitoring data show that food limits reproductive success in a boreal food-caching passerine




Derbyshire, Rachael

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University of Guelph


Food caching is a unique behaviour undertaken by several species of birds and mammals to overcome periods of food scarcity, but it is virtually unknown whether caching species are food-limited. The gray jay (Perisoreus canadensis) is a boreal resident passerine that stores food during the late summer and fall and breeds in late winter when fresh food is scarce. Using a two-year experiment and 43 years of monitoring data, we tested the food limitation hypothesis in a declining population of gray jays in Algonquin Provincial Park, ON, Canada. Females that were supplemented both experimentally and by park visitors laid eggs earlier in the season and raised more nestlings. Females that were supplemented by park visitors also had larger clutches than non-supplemented females. Nestling condition was not influenced by food supplementation. Our results support the food-limitation hypothesis and have important implications for understanding the mechanism driving the decline in this population.



Gray Jay, food supplementation, Perisoreus canadensis, population decline, public feeding, reproduction