Relationship between habitat and barn owl prey delivery rate and composition in a Napa Valley vineyard agroecosystem

Author

Dane A. R. St. George, Humboldt State UniversityFollow

Graduation Date

Fall 2019

Document Type

Thesis

Program

Master of Science degree with a major in Natural Resources, option Wildlife

Committee Chair Name

Matthew Johnson

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Jeffrey Black

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Barbara Clucas

Third Committee Member Affiliation

HSU Faculty or Staff

Subject Categories

Wildlife

Abstract

The provision of habitat for natural enemies of agricultural pests is common in integrated pest management approaches globally but has rarely been examined for vertebrate predators controlling vertebrate pests. To mitigate the economic and environmental costs of treating for rodent pests, winegrape producers in Napa Valley, California, have installed nest boxes to attract barn owls (Tyto alba) to their properties, but their effectiveness to control rodent pests in vineyards has not been thoroughly tested. A rigorous estimate of the number of rodents barn owls remove from the landscape is a necessary first step, and this study aimed to produce an index of rodent removal and prey composition by using remote nest box cameras. In addition, I tested hypotheses for how habitat may influence prey delivery rates and composition. Results indicate that each barn owl chick received 191 ± 10.01 prey items before dispersing from the nest box. Grassland habitat was an important predictor of prey delivery rate. Prey composition was dominated by voles, gophers, and mice, and their relative proportions were associated with the composition of habitats near a nesting box. Specifically, oak savannah was positively associated with the proportion of gophers, and negatively associated with voles and grassland was positively associated with voles. Further research should focus on the possible roles of rodent abundance, adult owl quality, and additional metrics of habitat structure on prey delivery rates.

Citation Style

Journal of Wildlife Management

Recommended Citation

St. George, Dane A. R., "Relationship between habitat and barn owl prey delivery rate and composition in a Napa Valley vineyard agroecosystem" (2019). Cal Poly Humboldt theses and projects. 351.
https://digitalcommons.humboldt.edu/etd/351