Analyzing Trends in Pigeon Guillemot (Cepphus columba) Abundance and Behavior Across Time and Tide Height

Abstract

Pigeon Guillemots (Cepphus columba) are widespread in the northern Pacific, occupying both natural and urban coastal habitats in the Salish Sea. Little research has addressed how abundance and behavior vary with habitat type, time-of-day, and tide height. For one week, we conducted systematic behavioral observations at a natural site and an urban site on San Juan Island. Abundance was consistently higher and more clumped at the natural site, indicating the higher-quality habitat. On the other hand, distributions of behavior were similar between sites, underlining the species’ ability to adapt to environmental changes. Foraging activity peaked in the early morning at high tide at both sites, while other behaviors were found to have no correlation with time-of-day or tide height. Our findings confirm patterns in abundance and behavior that were previously demonstrated in other regions, and emphasize the importance of preserving natural habitat and continued monitoring for a prevalent species.