Tracking data reveal high spatiotemporal consistency in migration of the threatened Taiga Bean Goose (Anser fabalis middendorffii) along the East Asian-Australasian flyway

Abstract

Migration consistency, the tendency of migratory birds to repeatedly use familiar breeding, stopover and wintering sites across years and seasons while maintaining a stable migration schedule, is advantageous as it minimizes the time and energy required to explore new environments, reduces mortality and improves overall fitness. Understanding migration consistency is essential for elucidating migration ecology, protecting migratory birds and their habitats. From 2017–2021, we tracked 24 Taiga Bean Geese breeding in the Mongolian-Russian taiga forest to analyze the duration of their four stages in annual cycle, migration parameters, spatial consistency and the temporal consistency of departure and arrival dates at summering and wintering sites. Furthermore, we evaluated the conservation status of the Taiga Bean Goose along its migration corridor. Our results revealed significant differences in the duration of the four annual cycle stages. The summering was the longest (138 ± 12 days), followed by the wintering (102 ± 13 days) and autumn migration (79 ± 13 days), while the spring migration was the shortest (47 ± 8 days). The geese exhibited high spatial consistency in migration routes and strong temporal consistency in departure from and arrival at summering sites, whereas the timing of arrival at and departure from wintering sites was more variable. Repeatedly used stopover sites across and within years were primarily located in the Hongyashan Reservoir and Hetao Plain in China, and the Orkhon River Valley in Mongolia. The stopover duration at repeatedly used sites in both seasons was significantly longer than that at sites used only in spring. Alarmingly, only 13 % of critical stopover sites currently fall within protected areas. Given the geese’s heavy reliance on the underprotected yet consistently utilized stopover sites across annual cycle, urgent conservation action is needed.