Arctic terns from circumpolar breeding colonies share common migratory routes

Authors: Wong et al.

Year: 2021

Publication: Marine Ecology Progress Series

Publication Link: https://doi.org/10.3354/meps13779

Keywords: Arctic tern · Migration · Timing · Geolocators · North America

Abstract: The Arctic tern is an iconic seabird, famous for its annual migrations between the
Arctic and the Antarctic. Its wide geographical range has impeded knowledge of potential population
bottlenecks during its annual bi-hemispheric movements. Although Arctic terns breed in
the Pacific, Atlantic, and Arctic coasts of North America, few tracking studies have been conducted
on North American Arctic terns, and none in Canada, which represents a significant proportion
of their circumpolar breeding range. Using light-level geolocators, we tracked 53 Arctic
terns from 5 breeding colonies across a wide latitudinal and longitudinal range within North
America. We compared the routes taken by birds in our study and migration timing to those previously
tracked from Greenland, Iceland, The Netherlands, Sweden, Norway, Maine (USA), and
S. Alaska (USA). Most Arctic terns tracked globally used one of 3 southbound migration routes: (1)
Atlantic West Africa; (2) Atlantic Brazil; and (3) Pacific coastal, and one of 2 northbound migration
routes: (1) Mid-ocean Atlantic and (2) Mid-ocean Pacific. Some other trans-equatorial seabirds
also used these migration routes, suggesting that Arctic tern routes may be important for other
species. The migration timing for southbound and northbound migrations was generally different
between tracked tern colonies worldwide but generally fell within a 1−2 mo window. Our re –
search suggests that conservation management of Arctic terns during their migration should
dynamically adapt with the times of the year that terns use parts of their route. Future identification
of common multi-species seabird flyways could aid the international negotiations required to
conserve pelagic seabirds such as Arctic terns.

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