Publication Date

4-30-2026

Document Type

Article

Publication Title

Marine Ecology Progress Series

Volume

784

DOI

10.3354/meps15130

Abstract

Understanding how prey selection influences foraging behavior is critical for assessing ecological flexibility in central place foragers. It can also inform how resources are partitioned among colonial breeding species like seabirds. The goal of the present study was to examine the spatial context and foraging effort by breeding pigeon guillemots Cepphus columba during the chick-provisioning period. We used a combination of miniature GPS loggers, time–depth recorders, and diet surveys of tracked individuals to test for associations between foraging location and prey selection. Guillemots were studied in 2023 and 2024 at Southeast Farallon Island, USA, where historical diet surveys indicate that juvenile rockfish and sculpin are primary prey items. From 559 foraging trips, we quantified trip duration, total distance traveled, distance to colony at prey capture location, travel time, maximum dive depth and duration, and foraging bout duration. Prey capture locations occurred within ~2 km of the island at diving depths of 19.07 ± 11.40 m. Model selection was used to evaluate how prey type, year, sex, hour, and their interactions explained variation in foraging effort and prey capture location. Corrected Akaike’s information criterion results favored models including hour and sex effects, with limited support for prey alone except when interacting with sex or year. Females traveled farther and dove deeper than males, while individuals in 2024 traveled greater distances and completed more dives than in 2023. This study shows sex-specific foraging strategies of breeding pigeon guillemots, revealing how males and females use nearshore habitats and adjust foraging behavior across years and prey types while provisioning chicks.

Funding Number

2023

Funding Sponsor

Council on Ocean Affairs Science and Technology, California State University

Keywords

Auk, Biologging, Diet, Diving behavior, Farallon Islands, Foraging ecology

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Biological Sciences

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