Strong Migratory Connectivity in a Declining Arctic Passerine

Abstract

Determining how animal populations are linked in space and time is important for identifying factors influencing population dynamics and for effective conservation and management. Arctic-breeding migratory passerines are declining and at risk due to forecasted climate change, but are a challenge to monitor due to their inaccessible breeding locations, long-distance migration routes and small body size. For the first time, we combine sub-gram geolocator technology and stable-isotope analysis with mark-recapture (banding) and citizen science data to determine patterns of migratory connectivity for multiple populations of a declining North American Arctic-breeding passerine, snow bunting (Plectrophenax nivalis). We show strong evidence for an east-west parallel migratory system, with Hudson Bay acting as a migratory divide. While band recoveries suggest strong migratory connectivity among eastern wintering populations (more than 95% of band recoveries reveal connections between western Greenland and eastern North America), novel application of geolocators and stable-hydrogen isotope analysis to a Canadian breeding population revealed a high degree of migratory connectivity within western North American wintering populations. Our results also show distinct differences in migratory distance between eastern and western populations, and illustrate how applying multiple techniques can effectively be used to track migration patterns of remote populations. Differences in annual distribution and migratory distance suggest that separate consideration of eastern and western wintering populations may improve future conservation and management efforts for this species.

From Svalbard to Siberia: Passerines breeding in the High Arctic also endure the extreme cold of the Western Steppe

“…Such itinerancy has been demonstrated over relatively small distances in wintering snow buntings [10, 68], however, within-winter movements in other small songbirds ranging from willow warblers Phylloscopus trochilus to the common cuckoo Cuculus canorus are better described as multiple non-breeding sites rather than the complex nomadic behaviour we reveal here [69–72]. This highlights the need for better understanding of within-winter movements across taxa, both at the microhabitat tracking scale (resources or climate) to longer flights in response to extreme conditions [1, 73].…”

“…These birds are present from late April until early September but spend the majority of the year away from their breeding grounds, as also recorded in North American birds [10]. The wintering grounds of the Svalbard population are unknown (one autumn and a few spring recoveries in Arkhangelsk; a few recovered in northern Norway in spring [12]).…”

Migration timing and wintering areas of three species of flycatchers (Tyrannus) breeding in the Great Plains of North America

“…The results of the present study raise several interesting questions for future research. (1) What drives the use of multiple wintering areas, and how do events in each wintering area carry over to the next wintering area and to the breeding grounds (e.g., Fraser et al 2012, Macdonald et al 2012, Callo et al 2013)? (2) What are the evolutionary mechanisms responsible for specific migratory and/or molt strategies (e.g., rate of migration)?…”

Combining direct and indirect tracking techniques to assess the impact of sub-Saharan conditions on cross-continental songbird migration

“…However, it is hampered by the indirect knowledge it provides of the geographical position of the bird. Overall, these limitations stress the importance of combining different methodologies in order to increase our understanding of movement ecology (Korner-Nievergelt et al 2012;Macdonald et al 2012; see e.g. Norris et al 2006;Woodworth et al 2016).…”