Department of Veterinary Medicine and Epidemiology, University of California Davis, 1 Shields Avenue, Davis, CA 95616, USA.
Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
Proc Biol Sci. 2022 Sep 14;289(1982):20220991. doi: 10.1098/rspb.2022.0991.
Nuanced understanding of seasonal movements of partially migratory birds is paramount to species and habitat conservation. Using nascent statistical methods, we identified migratory strategies of birds outfitted with radio-frequency identification (RFID) tags detected at RFID feeders in two sites in California, USA. We quantified proportions of migrants and residents and the seasonal phenology for each movement strategy in Allen's and Anna's hummingbirds; we also validated our methodology by fitting our model to obligate migratory black-chinned hummingbirds. Allen's and Anna's hummingbirds exhibited characteristics of facultative migratory behaviour. We also quantified apparent annual survival for each migratory strategy and found that residents had significantly higher probabilities of apparent survival. Low survival estimates for migrants suggest that a high proportion of birds in the migrant group permanently emigrated from our study sites. Considered together, our analyses suggest that hummingbirds in both northern and southern California sites partake in diverse and highly plastic migratory behaviours. Our assessment elucidates the dynamics underlying idiosyncratic migratory behaviours of two species of hummingbirds, in addition to describing a framework for similar assessments of migratory behaviours using the multi-state open robust design with state uncertainty model and single-site dynamics.
对部分迁徙鸟类季节性运动的细微理解对物种和栖息地保护至关重要。我们使用新兴的统计方法，通过在美国加利福尼亚州两个地点的 RFID 饲料器检测到配备 RFID 标签的鸟类，确定了鸟类的迁徙策略。我们量化了艾伦和安娜蜂鸟的迁徙者和居民比例，以及每种迁徙策略的季节性物候；我们还通过将我们的模型拟合到强制性迁徙的黑喉蜂鸟来验证我们的方法。艾伦和安娜蜂鸟表现出兼性迁徙行为的特征。我们还量化了每种迁徙策略的明显年度存活率，发现居民的明显存活率明显更高。迁徙者的低存活率估计表明，迁徙者群体中有很大一部分鸟类已永久离开我们的研究地点。综上所述，我们的分析表明，加利福尼亚州北部和南部地区的蜂鸟都参与了多样化和高度灵活的迁徙行为。我们的评估不仅描述了使用具有状态不确定性模型的多状态开放稳健设计和单站点动态的多状态开放稳健设计来评估迁徙行为的框架，还阐明了两种蜂鸟特有的迁徙行为背后的动态。
