Blondin Anne L, Drever Mark C, Flemming Scott A, Easton Wendy E, Maftei Mark, Zharikov Yuri, Warnock Nils, Nol Erica
Trent University Peterborough Ontario Canada.
Environment and Climate Change Canada Delta British Columbia Canada.
Ecol Evol. 2025 Jan 11;15(1):e70739. doi: 10.1002/ece3.70739. eCollection 2025 Jan.
An accurate estimate of length of stay is necessary to derive passage population size for birds using a migration stopover site. In this study, we used VHF tags and a Motus automated telemetry array to estimate the length of stay of 385 Western Sandpipers () migrating through two stopover sites in British Columbia, Canada (Tofino and Fraser River Estuary) over the course of seven migration periods (three northward and four southward) from 2018 to 2021. The average length of stay of Western Sandpipers at the Tofino site on the west coast of Vancouver Island varied from 2 to 6 days and was shorter than the length of stay at the Fraser River Estuary, where the average length of stay varied from 4 to 8 days. At both sites, adult birds had shorter stopovers during southward migration, juvenile birds had longer stopovers compared to adults, and birds with lower mass at capture had longer stopovers. Morphology of adults and juveniles varied between the two sites. Birds captured at Tofino had shorter tarsi, as well as higher mass during southward migration compared to Western Sandpipers captured at the Fraser River Estuary. We also assessed prey availability at the two stopover sites, and we found that invertebrate density was greater in Tofino compared to the Fraser River Estuary during northward migration. Variation in minimum stopover length and morphology between sites suggests that individuals from different overwintering populations may use different routes along the west coast of North America. Western Sandpipers stopping at Tofino have a shorter length of stay during both migration periods and arrive heavier during southward migration, characteristics typical of "hop" migrants who travel shorter distances between stopover sites. Different stopover sites offer a unique set of site characteristics used by birds exhibiting varying migration strategies, highlighting the importance of conserving a diversity of migration stopover locations.
要估算使用迁徙中途停歇地的鸟类的过往种群数量，准确估计停留时长是必要的。在本研究中，我们使用甚高频标签和Motus自动遥测阵列，对2018年至2021年七个迁徙期（三个向北和四个向南）期间，飞越加拿大不列颠哥伦比亚省两个中途停歇地（托菲诺和弗雷泽河河口）的385只西部鹬的停留时长进行了估算。温哥华岛西海岸托菲诺停歇地的西部鹬平均停留时长为2至6天，短于弗雷泽河河口停歇地，后者的平均停留时长为4至8天。在这两个停歇地，成年鸟在向南迁徙时停留时间较短，幼鸟的停留时间比成年鸟长，捕获时体重较轻的鸟停留时间更长。两个停歇地成年鸟和幼鸟的形态有所不同。与在弗雷泽河河口捕获的西部鹬相比，在托菲诺捕获的鸟跗跖较短，且在向南迁徙时体重更大。我们还评估了两个中途停歇地的猎物可利用性，发现在向北迁徙期间，托菲诺的无脊椎动物密度高于弗雷泽河河口。不同停歇地之间最短停留时长和形态的差异表明，来自不同越冬种群的个体可能沿着北美西海岸使用不同的路线。在托菲诺停歇的西部鹬在两个迁徙期的停留时长都较短，且在向南迁徙时到达时体重更大，这些是“跳跃式”迁徙者的典型特征，它们在停歇地之间飞行的距离较短。不同的中途停歇地提供了一系列独特的场地特征，供表现出不同迁徙策略的鸟类使用，这凸显了保护多种迁徙中途停歇地点的重要性。
