Sitting ducks: Strategies to increase recruitment in common eiders (Somateria mollissima) facing polar bear (Ursus maritimus) predation

The Canadian Arctic is warming at an increasing rate due to natural and anthropogenic drivers of climate change. In certain northern regions, these climatic shifts have led to earlier sea ice breakup and later freeze-up patterns which limits the time available for polar bears (Ursus maritimus) to hu...

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Bibliographic Details
Main Authors: Martin, Anik A., Barnas, Andrew F., Semeniuk, Christina A. D., Dr.
Format: Text
Language:unknown
Published: Scholarship at UWindsor 2022
Subjects:
Online Access:https://scholar.uwindsor.ca/uwilldiscover/2022/2022Day2/9
https://www.youtube.com/watch?v=-4QL6S2JqHw
Description
Summary:The Canadian Arctic is warming at an increasing rate due to natural and anthropogenic drivers of climate change. In certain northern regions, these climatic shifts have led to earlier sea ice breakup and later freeze-up patterns which limits the time available for polar bears (Ursus maritimus) to hunt their preferred marine-mammal prey. Consequently, bears experience a reduction in body condition, and as they are forced ashore earlier in the hunting season, are now compensating by consuming terrestrial resources such as common eider duck eggs (Somateria mollissima). This interaction can have serious negative consequences on the recruitment of common eiders as they have not yet adapted their nesting behaviours and anti-predator strategies to be effective against polar bears. Here, we use agent-based models in NetLogo 6.0.2 to simulate various common eider nesting behaviours that could reduce egg predation by polar bears. We examine how nesting distributions (clustered vs. random), lay dates (early vs. late), flight initiation distances, and flushing style (cryptic vs. conspicuous) influence nest failure due to polar bears. Data on individual eider nest success from each reproductive strategy will be analyzed to determine if behaviours exist that result in eider-agents capable of successfully avoiding nest predation. We hypothesize that eiders nesting in a random distribution with early lay dates that initiate flight when the polar bear is far using a cryptic flush decision will be the most successful. Our results will help highlight the adaptive capacity of eiders facing polar bear predation by identifying strategies that increase nest success.