Graduation Date
Summer 2024
Document Type
Thesis
Program
Master of Science degree with a major in Natural Resources, option Wildlife
Committee Chair Name
Barbara Clucas
Committee Chair Affiliation
HSU Faculty or Staff
Second Committee Member Name
Mark Colwell
Second Committee Member Affiliation
HSU Faculty or Staff
Third Committee Member Name
Ho Yi Wan
Third Committee Member Affiliation
HSU Faculty or Staff
Keywords
Raven, Western snowy plover, Resource selection, Behavior, Humboldt County, GPS tracking
Subject Categories
Wildlife
Abstract
Human food subsidies have allowed populations of the common raven (Corvus corax) to expand and increase in density, especially in the western United States, which has amplified predation risk for other native species. Common ravens are well-documented nest predators of the federally threatened Western snowy plover (Anarhynchus nivosus nivosus) in Humboldt County, California; however, little is known about raven movement and foraging behavior in and around snowy plover habitat. Using GPS tracking and behavioral surveys, I examined movement and foraging behavior of beach-going ravens across snowy plover nesting habitat and I explored raven diet through stable isotope analyses. Beach-going ravens had a large average home range size of 141 square km. and high variation between seasons and by age class, with larger movements observed in the non-breeding season and by sub-adult ravens. A Resource Selection Function revealed that ravens selected for snowy plover nesting areas and developed habitat, suggesting that ravens visiting snowy plover nesting areas are supported by human food sources in anthropogenic areas. Stable isotope diet analysis of tracked ravens revealed large variation between individuals at the trophic level and in overall diet composition. Ground-truthing of tracked raven locations revealed an abundance of both small and large-scale food resources throughout the study area, and observations of tagged ravens revealed territoriality of ravens at most snowy plover nesting beaches in the study area. Cumulatively, these results highlight the landscape-level features accessed by beach-going ravens and can inform management agencies on where to focus efforts for naturally managing raven populations.
Citation Style
APA
Recommended Citation
Chojnacki, Janelle, "Common raven resource selection, diet, and behavior around a threatened shorebird" (2024). Cal Poly Humboldt theses and projects. 770.
https://digitalcommons.humboldt.edu/etd/770