A Migratory Divide Among Red-Necked Phalaropes in the Western Palearctic Reveals Contrasting Migration and Wintering Movement Strategies

Abstract

Non-breeding movement strategies of migratory birds may be expected to be flexibly adjusted to the distribution and quality of habitat, but few studies compare movement strategies among populations using distinct migration routes and wintering areas. In our study, individual movement strategies of red-necked phalaropes (Phalaropus lobatus), a long-distance migratory wader which uses saline waters in the non-breeding period, were studied using light-level geolocators. Results revealed a migratory divide between two populations with distinct migration routes and wintering areas: one breeding in the north-eastern North Atlantic and migrating ca. 10,000 km oversea to the tropical eastern Pacific Ocean, and the other breeding in Fennoscandia and Russia migrating ca. 6,000 km-largely over land-to the Arabian Sea (Indian Ocean). In line with our expectations, the transoceanic migration between the North Atlantic and the Pacific was associated with proportionately longer wings, a more even spread of stopovers in autumn and a higher migration speed in spring compared to the migration between Fennoscandian-Russian breeding grounds and the Arabian Sea. In the wintering period, van Bemmelen et al. Contrasting Movement Strategies in Phalaropesbirds wintering in the Pacific were stationary in roughly a single area, whereas individuals wintering in the Arabian Sea moved extensively between different areas, reflecting differences in spatio-temporal variation in primary productivity between the two wintering areas. Our study is unique in showing how habitat distribution shapes movement strategies over the entire non-breeding period within a species.

Migration strategy and site fidelity of the globally threatened Sociable Lapwing Vanellus gregarius

“…This pattern has been demonstrated in, for example, Asian Houbara Bustard Chlamydotis macqueenii (Combreau et al 2011), a number of tundrabreeding species of the high Arctic (Alerstam & Gudmundsson 1999), European Bee-eater Merops apiaster (Hahn et al 2020) and many European-breeding passerines (Møller et al 2011). Red-necked Phalaropes Phalaropus lobatus in the western part of the European breeding range migrate westwards to the east Pacific and those in the eastern part of the European breeding range migrate south to the seas off Arabia and East Africa (van Bemmelen et al 2019). We believe that ours is one of very few studies, and perhaps the first, to demonstrate that the choice of intercontinental migration flyway may not be linked to longitude of breeding in adults or longitude of birth in chicks; birds tagged at the western and eastern limits of our sample were equally likely to be part of either flyway, and chicks born even within the same breeding colonies could later select different flyways.…”

Population‐specific migratory strategies of Twite Linaria flavirostris in Western Europe

“…) and, although within‐species disparities in migration strategy, or migratory divides, are less well understood, they are probably common (van Bemmelen et al . , Jiguet et al . ).…”

“…The strength of migratory connectivity varies between species (Finch et al 2017) and, although within-species disparities in migration strategy, or migratory divides, are less well understood, they are probably common (van Bemmelen et al 2019, Jiguet et al 2019. Non-breeding movements in migratory birds are thought to be flexible in response to habitat and resource availability, and therefore result in differing strategies between populations.…”

“…In Britain and Ireland, Twite are Red-listed (Eaton et al 2015) due to historical declines (Langston et al 2006, Wilkinson et al 2018 and range contraction (Brown et al 1995, Raine et al 2009), but the rate of decline varies between breeding populations (Wilkinson et al 2018). In the European Union, Twite are considered Vulnerable (VU); this assessment includes a geographically separate and seldom studied population of Twite in Turkish Asia Minor, at the extreme western end of the Asian population range (Ashpole et al 2015).…”

Interacting Roles of Breeding Geography and Early-Life Settlement in Godwit Migration Timing

“…Additionally, migration timing can vary by non-breeding site, particularly in populations with a large non-breeding range (e.g., Myers et al, 1985;Piersma et al, 2005;van Bemmelen et al, 2019). This is to be expected, as populations traveling farther ought to start migrating earlier if they require longer to reach the breeding grounds.…”