Senior Project Advisor
Leo Bodensteiner John McLaughlin
eagles, overwintering, Nooksack River
This paper provides a look into the demographics of overwintering eagles on the Nooksack River and their ties to salmon. Viewing overwintering eagles on the Nooksack River has become somewhat of a tradition for locals wanting to catch sight of these American icons in their natural habitat and consuming another PNW favorite; salmon. However, climate change and ever increasing ecological pressures have begun to alter the eagle-salmon food web dynamic in ways that are just starting to be explored. During the winter, eagles rely on the supply of salmon carcasses that wash onto the river banks and gravel bars after they spawn. This makes the Nooksack River an ideal location with its annual salmon runs. For my research, I investigated the demographics of eagles on a portion of the Nooksack River in Deming, WA. Between November and January I collected weekly observational data walking an approximate two mile stretch from the Deming Homestead Eagle Park to the Welcome Bridge. I recorded the number of eagles, where they were located, if they were juvenile or adult, general behavior, and weather and river height. From my findings I discovered a relationship between eagle numbers and river height which I hypothesize correlates to salmon carcass availability on gravel bars. I also found that in regards to habitat selection, more eagles were found on deciduous trees and juveniles and adult eagles were found in the same types of habitats. Juveniles and adults did differ in their groupings with juveniles found in more groups and adults in more pairs. Although the West side of the river had pedestrian access, the eagles did not appear to be on one side of the river over the other (East vs West). I also obtained escapement reports from Kendall Creek Hatchery and found potential correlations between return increases and eagle increases. Salmon are in decline due to various environmental stressors but there are gaps in research on what happens to the species reliant on their spawning returns. Observational research such as mine can inform scientists and policy makers on the trophic level effects of salmon availability changes, specifically in the overwinter eagle populations.
Webb, Collette, "Overwintering Eagle Demographics on the Nooksack River" (2023). WWU Honors College Senior Projects. 644.
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