CRB: Habitat Selection of Landbird Migrants

迁徙期间栖息地的使用对鸟类满足能量需求的能力、对捕食者的脆弱性以及暴露在环境压力下的能力具有深远的影响。这项拟议的研究量化了春季和秋季途中的栖息地使用情况。据推测，移民之所以选择特定的栖息地，是因为他们因此增强了自己的健康状况。虽然很难直接衡量在途中利用栖息地对生存和繁殖成功的影响，但可以评估迁徙过程中如何有效地满足迁徙期间的能源需求，即储存脂肪储备和增加体重的直接后果。超过一半的北美地鸟是长途候鸟，他们在温度繁殖区和更多的热带越冬区之间旅行。新热带土鸟候鸟数量的减少与越冬地栖息地的丧失和森林繁殖地的碎片化有关。由于候鸟种群的持久性取决于鸟类在整个年度周期中找到有利条件的能力，与候鸟迁徙途中生态相关的因素必须在制定合理的保护政策时考虑在内。

Habitat use during migration has profound consequences for a bird's ability to satisfy energy requirements, vulnerability to predators, and exposure to environmental stress. The proposed research quantifies habitat use during spring and fall en route periods. Presumably migrants select particular habitats because they thereby enhance their fitness. Although it would be difficult to measure directly the effect of en route use of habitat on survival and reproductive success, it is possible to evaluate the immediate consequences in relation to how effectively migrants satisfy energy demand during migration, i.e. deposit fat reserves and gain body mass. Over half of all North American landbirds are long-distance migrants that journey between temperature breeding ranges and more tropical wintering areas. Decline in populations of Neotropical landbird migrants is linked to habitat loss on the wintering grounds and fragmentation of forested breeding habitats. Because the persistence of migrant populations depends on the bird's ability to find favorable conditions throughout the annual cycle, factors associated with the en route ecology of migrants must figure in the formulation of sound conservation policy.