Feeding specialization is a common cause of individual variation. Fitness payoffs of specialization vary with environmental conditions, but the underlying behavioral mechanisms are poorly understood. Such mechanistic knowledge, however, is crucial to reliably predict responses of heterogeneous populations to environmental change. We quantified spatiotemporal allocation of foraging behavior in wintering Eurasian oystercatchers (Haematopus ostralegus), a species in which feeding specialization can be inferred from bill shape. We combined global positioning system (GPS) and accelerometer data to quantify foraging time of 64 individuals for every tidal period in one or two winter seasons. Individuals varied widely in foraging time (3.7–6.5 h per tidal period) and individuals that spend more time foraging had lower inferred survival. Feeding specialization appeared a major determinant of individual variation in foraging time and its spatiotemporal allocation. Visually hunting worm specialists foraged more during day time and complemented intertidal foraging with grassland foraging when the exposure of intertidal flats was limited and nights were well illuminated. Shellfish specialists increased total foraging time in cold weather, whereas foraging time of worm specialists decreased as frosty grasslands became inaccessible. Our results imply that worm specialists may be most sensitive to cold snaps and daytime disturbance, whereas shellfish specialists are most sensitive to high water levels. These behavioral responses can be implemented in population models to predict the vulnerability of heterogeneous populations to environmental change and, thereby, provide a shortcut to long-term population studies that require fitness data across many years and conditions to make similar projections.

中文翻译：

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水鸟饲养专家在环境条件如何改变其觅食时间方面存在差异

饲养专业化是个体变异的常见原因。专业化的健身收益因环境条件而异，但对潜在的行为机制知之甚少。然而，这种机械知识对于可靠地预测异质种群对环境变化的反应至关重要。我们量化了越冬的欧亚牡蛎（Haematopus ostralegus）觅食行为的时空分配，这是一种可以从喙形状推断出觅食专业化的物种。我们结合全球定位系统 (GPS) 和加速度计数据，量化了 64 只个体在一两个冬季的每个潮汐周期的觅食时间。个体在觅食时间（每个潮汐周期 3.7-6.5 小时）方面差异很大，花费更多时间觅食的个体推断存活率较低。饲养专业化似乎是觅食时间及其时空分配个体差异的主要决定因素。视觉捕食蠕虫专家在白天觅食更多，当潮间带暴露有限且夜晚光线充足时，潮间带觅食与草地觅食相辅相成。贝类专家在寒冷天气下增加了总觅食时间，而蠕虫专家的觅食时间随着寒冷的草原变得无法进入而减少。我们的结果意味着蠕虫专家可能对寒流和白天干扰最敏感，而贝类专家对高水位最敏感。这些行为反应可以在种群模型中实施，以预测异质种群对环境变化的脆弱性，从而，