Does optimal foraging theory explain why suburban Florida scrub-jays (Aphelocomacoerulescens) feed their young human-provided food?
Does optimal foraging theory explain why suburban Florida scrub-jays (Aphelocomacoerulescens) feed their young human-provided food?
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最佳觅食理论能否解释为什么佛罗里达郊区的灌丛鸦（Aphelocomacoerulescens）会以人类提供的食物喂养它们的幼崽？
DOI：
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发表时间：
2006
影响因子：
2.3
通讯作者：
Gilberto Pasinelli
中科院分区：
文献类型：
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作者：
Annette Sauter;R. Bowman;S. Schoech;Gilberto Pasinelli
最优觅食理论假设觅食者可以充分评估猎物的质量，并预测只有当父母的供应能力意外下降时，才会给他们的幼崽喂食低质量的食物。佛罗里达荒野灌木鸟只喂食幼小的节肢动物，但郊区的父母在雏鸟的饮食中包括人类提供的食物，可能会降低生长和生存的成本。考虑到明显的成本，我们通过实验测试了父母是否喂养人类提供的食物，因为：1)他们不区分食物类型，2)当环境中天然食物的可获得性较低时，他们会转向低质量、丰富的食物，或3)当获得天然食物所需的时间较长时，他们会改变。父母在养育孩子时表现出对天然食物的偏爱，从而区分了天然食物和人类提供的食物。当试验性地增加处理天然食物的时间时，郊区和荒野栖息地的父母转向人类提供的食物。在两个栖息地补充天然食物增加了对这种食物的偏好。郊区的父母比荒野的父母选择更多的天然食物，这表明他们更喜欢天然食物。不管喂食者表现出的偏好如何，郊区和荒野的父母给雏鸟提供的大多是天然食物，而不是天然食物的供应。尽管如此，天然食物在环境中可能比我们的实验测试中更稀缺。由于郊区自然食物的可获得性低于荒野栖息地，郊区的父母在喂养雏鸟时可能会被迫改用人类提供的食物。
Optimal foraging theory assumes that a forager can adequately assess the quality of its prey and predicts that parents feed their young low-quality foods only when suffering unpredicted reductions in their ability to provision. Wildland Florida scrub-jays feed their young exclusively arthropods, but suburban parents include human-provided foods in the nestling diet, with possible costs in terms of reduced growth and survival. We tested experimentally whether parents feed human-provided foods, given the apparent costs, because: 1) they do not discriminate between food types, 2) they switch to low-quality, abundant foods when natural food availability in the environment is low, or 3) they switch when the time needed to obtain natural food is high. Parents discriminated between natural and human-provided foods by showing a preference for natural foods when rearing young. When the handling time of natural foods was increased experimentally, parents in the suburban and wildland habitats switched to human-provided foods. Supplementation with natural foods increased preference for this food in both habitats. Suburban parents chose more natural foods than wildland parents, suggesting that they have a greater preference for natural foods. Regardless of preferences demonstrated at feeders, parents in both the suburbs and wildlands delivered mostly natural foods to nestlings, independent of natural food availability. Nonetheless, natural foods are likely to be scarcer in the environment than in our experimental tests. Because natural food availability is lower in the suburbs than in the wildland habitat, parents in the suburbs may be forced to switch to human-provided foods when feeding nestlings.