Bird migration strategies: linking individual decisions and population processes

移徙是一种现象，使个人能够预测或应对资源变化、疾病或捕食风险以及不适宜居住的条件。因此，迁徙策略各不相同，发展迅速，并影响人口动态。鸟类种群通常完全由义务候鸟组成，但越来越明显的是，由候鸟和留鸟组成的部分候鸟种群也很常见。这就提出了更多的问题。为什么有些人会迁徙而另一些人不会？个体的迁徙策略是否会随着环境条件的变化而改变？移徙者的流动如何影响其他人口和社区？我的研究计划旨在了解支撑迁移变化的生态过程，调查气候和土地利用变化如何影响迁移策略，并评估人为压力源和迁移策略如何相互作用以影响个人，人群和社区。******我建议对黑牡蛎捕鱼者进行研究，以评估部分迁移的假设，确定迁移在多大程度上是一种固定的或随气候条件变化的可塑性特征，并检查迁移对个体和种群的影响。我们将研究阿拉斯加和不列颠哥伦比亚省的捕牡蛎者，阿拉斯加的繁殖种群由居民和移民组成，而不列颠哥伦比亚省的越冬种群由居民和来自更远北方的移民组成。我们将使用跟踪标签和稳定同位素的组合来确定个体是否迁移，并询问迁移的决定是否随环境条件或个体的大小、年龄和性别而变化。我们将使用最先进的卫星标签来评估阿拉斯加移民的存在和密度如何影响不列颠哥伦比亚省居民冬季栖息地的使用。监测跨年和亚种群的生存和繁殖将使我们能够评估迁徙选择是否能够维持多种迁徙策略，或者气候变化是否有利于增加居住水平。这项研究将促进我们对迁移的理解，并为预测部分迁移人口对环境变化的复杂反应提供模型。******我还建议研究季节性候鸟的到来如何影响热带地区的鸟类群落，这些候鸟会使墨西哥越冬地的鸣禽密度增加一倍。这项工作在墨西哥哈利斯科州进行，将研究与干旱森林有关的留鸟群落如何随着这种受威胁的栖息地转变为农业而变化。我们还将询问迁徙的帕塞丽娜狩猎的到来如何影响当地居民的行为、状况和生存，即橙胸狩猎。这项工作将确定景观变化和候鸟和留鸟之间的种间竞争如何影响热带地区的鸟类群落。* * * * * * * *

Migration is a phenomenon that allows individuals to anticipate or respond to variation in resources, disease or predation risk, and inhospitable conditions. Migratory strategies therefore vary, evolve rapidly, and affect population dynamics. Bird populations are often composed entirely of obligate migrants, but it is increasingly apparent that partially migratory populations, composed of both migrants and residents, are common. This poses further questions. Why do some individuals migrate while others do not? Does the migratory strategy of an individual change in response to environmental conditions? How does the movement of migrants influence other populations and communities? My research program aims to understand the ecological processes that underpin variation in migration, investigate how climate and land use change influence migratory strategies, and evaluate how anthropogenic stressors and migratory strategies interact to influence individuals, populations and communities.******I propose research on black oystercatchers that will evaluate hypotheses for partial migration, determine the degree to which migration is a fixed or plastic trait that varies with climatic conditions, and examine the consequences of migration for individuals and populations. We will study oystercatchers both in Alaska, where the breeding population is composed of residents and migrants, and in BC, where the wintering population is composed of residents and migrants from further north. We will determine whether individuals migrate or not using a combination of tracking tags and stable isotopes, and ask if the decision to migrate varies with environmental conditions or the size, age and sex of an individual. We will use state of the art satellite tags to evaluate how the presence and density of migrants from Alaska influences the winter habitat use of residents in BC. Monitoring of survival and reproduction across years and sub-populations will allow us to evaluate whether selection for migration can maintain multiple migratory strategies or climate change will favour increased levels of residency. This research will advance our understanding of migration and inform models that can forecast how complex partially migratory populations will respond to environmental change. ******I also propose research that will examine how the arrival of seasonal migrants, that can double the density of songbirds on the wintering grounds in Mexico, influences avian communities in the tropics. This work, conducted in Jalisco, Mexico, will examine how the resident bird community associated with dry forests changes as this threatened habitat is converted to agriculture. We will also ask how the arrival of migratory Passserina buntings influences the behavior, condition and survival of an endemic resident, the orange-breasted bunting. This work will determine how landscape change and inter-specific competition between migratory and resident birds influence bird communities in the tropics. ********