The Effects of Diet and Predation on Nesting Herring Gulls (Larus argentatus) in Pukaskwa National Park

Herring gulls (Larus argentatus) are used as ecological indicators of the coastal Lake Superior ecosystem in Pukaskwa National Park. Their populations have declined by 70% over the last 40 years, suggesting changes in the park ecosystem. I assessed herring gull diets and investigated how diet may influence population trends through effects on life-history endpoints. I additionally investigated the degree to which predation is affecting herring gull reproductive success by examining gull nest attentiveness with camera traps. Gulls utilizing anthropogenic food sources exhibited reduced levels of stress-associated hormones, increased egg size, and increased day-time nest attentiveness. Gulls were significantly more attentive to their nests during the day compared to the night. Nocturnal predation by great horned owls was the most significant predation-related factor affecting herring gull nest success. Understanding factors contributing to population trends in ecological indicator species is critical for identifying stressors that are likely affecting the broader ecosystem.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Master's

Discipline thesis:degree_discipline

Biology

Grantor dc:publisher

Carleton University

Year dc:date.issued

2022

Author dc:creator

• Serre, Serina Juliette

Statement dc:rights

• Copyright © 2022 the author(s). Theses may be used for non-commercial research, educational, or related academic purposes only. Such uses include personal study, research, scholarship, and teaching. Theses may only be shared by linking to Carleton University Institutional Repository and no part may be used without proper attribution to the author. No part may be used for commercial purposes directly or indirectly via a for-profit platform; no adaptation or derivative works are permitted without consent from the copyright owner.

Language dc:language.iso

en

DOI

10.22215/etd/2022-15231

OAI identifier oai:identifier

oai:carleton.scholaris.ca:20.500.14718/41932