Date of Award

2-5-2025

Publication Type

Thesis

Degree Name

M.Sc.

Department

Biological Sciences

Keywords

Adaptive Capacity; Arctic Seaduck; Climate Change; Common Eider; Habitat Selection; Nest Quality

Supervisor

Christina Semeniuk

Rights

info:eu-repo/semantics/openAccess

Abstract

The Northern common eider (Somateria mollissima borealis) is an Arctic-breeding sea duck that balances trade-offs between thermal protection and predation avoidance in its nest-site selection. While the landscape features driving these preferences have been characterized, it remains unclear whether nest-site selection has changed in response to warming temperatures and increased risk from novel predators during the breeding season. This study examines long-term patterns of nest-site selection amongst five monitored nesting areas at East Bay Island, Nunavut, from 1999 to 2023, with a focus on habitat (climate and landscape) drivers and changes in nest-site preferences. Our results revealed heterogeneity exists among the five nesting areas on EBI, characterized mainly by differences in landscape attributes; and that over time, eiders switched nesting preferences amongst these sites. We furthermore revealed these shifts were driven by hens increasingly selecting for reduced visibility, denser vegetation, and improved wind cover, indicating a shift toward prioritizing protection against predation. These changes most likely coincide with increased polar-bear predation, suggesting an adaptive response to heightened predation pressures. Interestingly, climate variables were unable to describe site heterogeneity or explain preferences in site quality, suggesting that for nesting eiders, climate may not yet be a significant stressor. This study highlights the complexity of nest-site selection in Arctic-breeding eiders in face of multiple stressors, and underscores the importance of continual monitoring and protection critical habitat features that reflect increasing pressures due to climate change. Understanding these dynamics can inform conservation strategies to support the adaptive capacity of eiders in rapidly changing Arctic ecosystems.

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