Annual Winter Site Fidelity of Barrow's Goldeneyes in the Pacific

Abstract

Coastal regions on the Pacific north coast of North America provide important wintering habitat for many species of sea ducks. Although winter range and habitat preferences are well described for most species, fidelity to coastal wintering sites is generally undocumented. Fidelity is an important factor necessary for understanding interactions with coastal developments and activities and corresponding management strategies. We used data from Barrow's goldeneyes (Bucephala islandica), a sea duck that winters predominantly in nearshore habitats along the Pacific north coast, to investigate inter‐annual fidelity to, and intra‐annual fidelity within, coastal wintering sites. Between 2006 and 2015, we marked goldeneyes on breeding, molting, and wintering sites with satellite transmitters. We retained 4,931 locations in coastal habitats from 221 goldeneyes across 4 coastal regions for our analyses. These birds demonstrated high inter‐annual fidelity to coastal wintering sites; 75% of selected wintering sites were within 29 km of sites used the previous winter. Inter‐annual fidelity to wintering sites was similar between sex and age classes but differed by coastal region. Goldeneyes from southcentral Alaska, USA, expressed greater inter‐annual fidelity relative to birds from northern or southern British Columbia, Canada, and southeast Alaska. Goldeneyes also expressed high intra‐annual fidelity within wintering sites, with 75% of individuals averaging within‐season movements of ≤9 km. Intra‐annual fidelity was lesser for female than male goldeneyes but did not differ between hatch‐year and after‐hatch‐year birds. We found regional variation in intra‐annual fidelity, with goldeneyes from southcentral Alaska expressing greater intra‐annual fidelity compared to birds from other regions. High inter‐ and intra‐annual winter site fidelity by Barrow's goldeneyes suggests that, at a population level, habitat use is predictable and can be used to inform risk assessment or to evaluate factors affecting habitat choice. Also, low dispersal among wintering sites suggests that recovery from population perturbations, whether caused by natural or anthropogenic events, will be protracted. © 2019 The Wildlife Society.

Twenty years of coastal waterbird trends suggest regional patterns of environmental pressure in British Columbia, Canada

“…First, we predicted that abundance declines will be more prevalent in higher tropic feeders because this guild is generally more responsive to shifts in the availability and quality of prey (e.g., Ballance et al 1997, Hyrenbach and Veit 2003, Ainley and Hyrenbach 2010, Vilchis et al 2015. Second, we predicted that abundance declines will be more pronounced in migrants because these populations are able to shift their range in response to resource availability more readily than local breeders can (e.g., Burger and Gochfeld 1991, Marks and Redmond 1994, Willie et al 2020. Finally, we discuss potential mechanisms to stimulate future research and to inform conservation planning.…”

High site fidelity does not equate to population genetic structure for common goldeneye and Barrow's goldeneye in North America

“…We posit that the mtDNA structure could have been a temporary signal as male mtDNA haplotypes are not passed onto the next generation (albeit this happens rarely), and that a female only assessment that distinguishes between patterns of population structure on breeding and wintering grounds is necessary to confirm which sex (if either) is the primary dispersing agent over a broad time scale. Finally, given that telemetry data suggest females and to some extent adult males display high regional fidelity (Willie et al 2020), we contend that males, more likely immature males, are the primary dispersing agent maintaining nuclear similarity across each species' respective ranges.…”

“…Male‐biased dispersal does not fully explain the observed patterns of discord as Barrow's goldeneye exhibit high rates of breeding site fidelity in both sexes, with the average yearly return rate for adult males (67% ± 11%) nearly identical to that of females (63% ± 4%; Savard and Eadie 1989). The high fidelity of adult males to nesting areas may result from long‐term pair bonds exhibited by Barrow's goldeneye, as both sexes have high wintering site fidelity (Willie et al 2020). Additionally, male Barrow's goldeneye vigorously defend territories and are therefore more likely to reunite on the wintering grounds where mate selection occurs (Savard 1985).…”

“…The same study also showed no overlap in winter band recoveries among individuals marked in Alaska and British Columbia during the summer (Pearce et al 2014). Additionally, satellite telemetry has shown high inter‐annual winter site fidelity for Pacific Barrow's goldeneye (Willie et al 2020). However, there was some overlap in recovery for common goldeneye marked in central Canada and eastern North America (Pearce et al 2014), suggesting that common goldeneye exhibit dispersal to multiple wintering areas on both coasts.…”

Pacific Barrow’s Goldeneye refine migratory phenology in response to overwintering temperatures and annual snowmelt

“…Pairs are suspected to then reunite on their wintering grounds (Savard 1985). Both sexes display fidelity to wintering, breeding, and molting locations as adults (Savard 1985, Willie et al 2020), although natal philopatry is higher in females than in males (Boyd et al 2009). When overwintering, their diet consists largely of mollusks while during both breeding and molting stages, Barrow's Goldeneye consume primarily insects (Eadie et al 2020).…”