The plastic regulation of internal energy reserves is acknowledged as the main adaptive response to winter conditions of resident small birds in northern latitudes, a strategy that may be altered whenever human‐supplemented food is available. We investigated the effects of supplementary feeding on the energy management strategy of two wild passerine species, the Willow Tit Poecile montanus and Blue Tit Cyanistes caeruleus, wintering in boreal conditions by measuring body mass and the energy cost of living, i.e. basal metabolic rate. Individuals of both species were heavier, larger and exhibited a higher energy cost of living when captured at the feeders than were individuals captured away from feeders. Fed Willow Tits expended more energy in maintenance, although this difference disappeared once mass was accounted for. Conversely, Blue Tits at feeders had higher mass‐adjusted energy cost of living, but only at low ambient temperatures. The results indicate that winter feeding has species‐specific effects on overall energy management strategy and modifies the response to environmental conditions of wintering passerines.

中文翻译：

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冬季喂养会影响北方雀形目鸟的生活成本

内部能量储备的塑料调节被认为是对北纬地区常驻小鸟冬季条件的主要适应性反应，只要有人类补充的食物，该策略就可能改变。我们研究了两种野生雀形目种类的能源管理战略补充营养的效果，柳山雀Poecile麻雀和蓝山雀Cyanistes青色，通过测量体重和生活所需的能量（即基础代谢率），在北方条件下越冬。与从饲养场捕获的个体相比，在饲养场捕获的两种物种的个体更重，更大，并且表现出更高的生活能源成本。美联储Willow Tits花费了更多精力进行维护，尽管一旦考虑了质量，这种差异就消失了。相反，馈线中的蓝雀具有较高的质量调整后的生活能源成本，但仅在较低的环境温度下才有效。结果表明，冬季饲喂对总体能量管理策略具有特定物种的影响，并改变了对越冬雀形目对环境条件的响应。