Food availability early in life can play a vital role in an individual's development and success, but experimental evidence for the direct effects of food on body condition, physiology, and survival of young animals in the wild is still relatively scarce. Food-caching Canada jays (Perisoreus canadensis) begin breeding in the late winter and, therefore, rely on either cached food or seemingly limited quantities of fresh food to feed nestlings in the early spring. Using a two-year food supplementation experiment conducted during the nestling period and 40 years of observational data on food supplemented by the public, we examined whether food quantity during early life influenced the physiology, body condition, timing of fledging and survival of young Canada jays in Algonquin Provincial Park, ON. Experimental food supplementation of breeding pairs advanced the fledging date of young by 24% (5.5 d) compared to controls. In one year of the experiment, nestlings raised on experimentally supplemented territories had lower feather corticosterone concentrations and were in higher body condition than controls. Across treatment and control nests, young that successfully fledged had lower concentrations of feather corticosterone and were in higher body condition than those that did not fledge. Based on 40 years of observational data, nestling body condition was positively related to the degree of food supplementation by park visitors and nestlings in higher body condition were more likely to be observed in the population in the following fall. Our results demonstrate how food availability early in life can have important downstream consequences on metrics related to individual fitness, including first year survival.

中文翻译：

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以有限的资源养育幼鸟：补充剂可改善身体状况并促进加拿大松鸦的发育

生命早期的食物供应对个体的发展和成功起着至关重要的作用，但食物对野外幼小动物的身体状况、生理和生存的直接影响的实验证据仍然相对稀少。食物缓存加拿大松鸦 (Perisoreus canadensis) 在冬末开始繁殖，因此，在早春依靠缓存食物或看似数量有限的新鲜食物来喂养雏鸟。使用在雏鸟时期进行的为期两年的食物补充实验和 40 年公众补充食物的观察数据，我们研究了幼年加拿大松鸦在生命早期的食物数量是否影响生理、身体状况、羽化时间和存活率在阿冈昆省立公园，ON。与对照相比，繁殖对的实验性食物补充使幼鸟的羽化日期提前了 24%（5.5 天）。在一年的实验中，在实验补充的领土上饲养的雏鸟羽毛皮质酮浓度较低，身体状况比对照组更高。在处理和控制巢中，成功羽化的幼鸟的羽毛皮质酮浓度较低，身体状况也比未羽化的幼鸟高。根据 40 年的观察数据，雏鸟体况与公园游客的食物补充程度呈正相关，并且在随后的秋季更容易在人群中观察到体况较高的雏鸟。