Saracco James F, Cormier Renée L, Humple Diana L, Stock Sarah, Taylor Ron, Siegel Rodney B
The Institute for Bird Populations Petaluma California USA.
Point Blue Conservation Science Petaluma California USA.
Ecol Evol. 2022 Jun 11;12(6):e8934. doi: 10.1002/ece3.8934. eCollection 2022 Jul.
The demography and dynamics of migratory bird populations depend on patterns of movement and habitat quality across the annual cycle. We leveraged archival GPS-tagging data, climate data, remote-sensed vegetation data, and bird-banding data to better understand the dynamics of black-headed grosbeak () populations in two breeding regions, the coast and Central Valley of California (Coastal California) and the Sierra Nevada mountain range (Sierra Nevada), over 28 years (1992-2019). Drought conditions across the annual cycle and rainfall timing on the molting grounds influenced seasonal habitat characteristics, including vegetation greenness and phenology (maturity dates). We developed a novel integrated population model with population state informed by adult capture data, recruitment rates informed by age-specific capture data and climate covariates, and survival rates informed by adult capture-mark-recapture data and climate covariates. Population size was relatively variable among years for Coastal California, where numbers of recruits and survivors were positively correlated, and years of population increase were largely driven by recruitment. In the Sierra Nevada, population size was more consistent and showed stronger evidence of population regulation (numbers of recruits and survivors negatively correlated). Neither region showed evidence of long-term population trend. We found only weak support for most climate-demographic rate relationships. However, recruitment rates for the Coastal California region were higher when rainfall was relatively early on the molting grounds and when wintering grounds were relatively cool and wet. We suggest that our approach of integrating movement, climate, and demographic data within a novel modeling framework can provide a useful method for better understanding the dynamics of broadly distributed migratory species.
候鸟种群的人口统计学特征和动态变化取决于其在年度周期内的迁徙模式和栖息地质量。我们利用存档的GPS标记数据、气候数据、遥感植被数据和鸟类环志数据，以更好地了解黑头蜡嘴雀（ ）在两个繁殖区域——加利福尼亚州的海岸和中央谷地（加利福尼亚海岸）以及内华达山脉（内华达山脉）——28年（1992 - 2019年）间的种群动态。年度周期内的干旱状况以及换羽地的降雨时间影响了季节性栖息地特征，包括植被绿度和物候（成熟日期）。我们开发了一种新颖的综合种群模型，其中种群状态由成年个体捕获数据提供信息，招募率由特定年龄捕获数据和气候协变量提供信息，生存率由成年个体标记重捕数据和气候协变量提供信息。加利福尼亚海岸的种群数量在年份间相对变化较大，其中新加入个体和存活个体数量呈正相关，种群增长年份主要由招募驱动。在内华达山脉，种群数量更为稳定，并且显示出更强的种群调节证据（新加入个体和存活个体数量呈负相关）。两个区域均未显示出长期种群趋势的证据。我们发现大多数气候 - 人口统计学速率关系的支持证据较弱。然而，当换羽地降雨相对较早且越冬地相对凉爽湿润时，加利福尼亚海岸地区的招募率较高。我们认为，我们在一个新颖的建模框架内整合迁徙、气候和人口统计数据的方法，可为更好地理解广泛分布的迁徙物种的动态变化提供一种有用的方法。
