Annual cycle of White-winged Scoters (Melanitta fusca) in eastern North America: migratory phenology, population delineation, and connectivity

Abstract

Understanding full annual cycle movements of long-distance migrants is essential for delineating populations, assessing connectivity, evaluating crossover effects between life stages, and informing management strategies for vulnerable or declining species. We used implanted satellite transmitters to track up to 2 years of annual cycle movements of 52 adult female White-winged Scoters (Melanitta fusca (Linnaeus, 1758)) captured in the eastern United States and Canada. We used these data to document annual cycle phenology; delineate migration routes; identify primary areas used during winter, stopover, breeding, and molt; and assess the strength of migratory connectivity and spatial population structure. Most White-winged Scoters wintered along the Atlantic coast from Nova Scotia to southern New England, with some on Lake Ontario. White-winged Scoters followed four migration routes to breeding areas from Quebec to the Northwest Territories. Principal postbreeding molting areas were in James Bay and the St. Lawrence River estuary. Migration phenology was synchronous regardless of winter or breeding origin. Cluster analyses delineated two primary breeding areas: one molting area and one wintering area. White-winged Scoters demonstrated overall weak to moderate connectivity among life stages, with molting to wintering connectivity the strongest. Thus, White-winged Scoters that winter in eastern North America appear to constitute a single continuous population.

Spatially explicit network analysis reveals multi‐species annual cycle movement patterns of sea ducks

“…, Meattey et al. ). However, the complete dataset provides a unique opportunity to examine and compare movement patterns across several sympatric species tracked simultaneously.…”

“…Since 2002, the project and other associated tracking efforts have collected annual cycle movement data from 672 individual birds representing five species, including Common Eider (Somateria mollissima), Black Scoter (Melanitta americana), Surf Scoter (M. perspicillata), White-winged Scoter (M. deglandi), and Long-tailed Duck (Clangula hyemalis). To date, analyses of these data have focused on species-specific movement patterns and habitat use (Loring et al 2014, Beuth et al 2017, Spiegel et al 2017, Meattey et al 2018). However, the complete dataset provides a unique opportunity to examine and compare movement patterns across several sympatric species tracked simultaneously.…”

First Report of Scoters (<i>Melanitta</i> spp.) along Eastern Baffin Island, Nunavut, Canada

“…In eastern Canada, the known northern range limit for White-winged Scoter is approximately 55˚ -59˚ N along the coast of Labrador (Lock, 1986;Brown and Fredrickson, 2019). Across Canada, its breeding distribution follows the northern limits of the treeline (Meattey et al, 2018;Richards and Gaston, 2018;S. Gilliland, unpubl.…”

“…Expedition ship travel in the Arctic has been increasing in frequency and area covered (Dawson et al, 2018), and data from these trips are proving useful for mapping marine bird distributions, population trends, and threats they may face in the Arctic (Chardine et al, 2004;Wong et al, 2018). Here, we report on two extralimital observations of sea ducks in eastern Nunavut, much farther north than previously noted and disparate from locations detected by satellite telemetry (e.g., Meattey et al, 2018).…”

Annual‐Cycle Movements and Phenology of Black Scoters in Eastern North America

“…We classified coastal or inland habitats occupied following breeding or, if breeding was not attempted, pre‐breeding migration as either molting or post‐breeding staging. To distinguish remigial molt sites from post‐breeding staging areas, we used criteria derived from observations of closely related scoter species and defined molt sites as those used for ≥48 consecutive days, with arrival dates between July and September and departure dates between August and October (Dickson et al 2012, Meattey et al 2018). In all cases, we excluded the season in which a bird was captured from analysis; for individuals captured during winter, we assessed chronology and site use beginning with pre‐breeding migration, and for individuals captured at pre‐breeding or post‐breeding staging sites we began with the subsequent breeding or wintering season.…”