QUANTIFYING RELATIONSHIP BETWEEN HABITAT AND PREY REMOVAL OF NESTING BARN OWLS IN NAPA VALLEY VINEYARDS.
Dane A. St. George; Humboldt State University; 1 Harpst Street, Wildlife Department, Arcata, CA, 95521; (585) 402-5919; das984@humboldt.edu; Matthew D. Johnson
Habitat provision for natural enemies of agricultural pests is a common practice in integrated pest management (IPM) solutions. Winegrape farmers in Napa Valley, California have installed nest boxes in vineyards to attract barn owls (Tyto alba) to help manage economically damaging rodents, but the magnitude of the pest control service delivered by barn owls has yet to be rigorously tested. We used nest box cameras to document prey delivery rates of nesting barn owls to provide an index of rodent removal and prey species composition. Preliminary data suggest that individual chicks receive 157 prey deliveries from the time of hatch until dispersal, consisting primarily of voles (Microtus sp.) and pocket gophers (Thomomys bottae). Prey delivery rate peaked between weeks four and five with a peak average of 7.35 prey deliveries per chick per night and overall average of 2.85 prey deliveries per chick per night. Data also suggest that landscape heterogeneity may contribute to variation in prey delivery rate. Elucidating these trends may help with the strategic placement of nest boxes in vineyards and incentivize farmers to conserve habitat important for nesting barn owls and other local wildlife.
Ecology and Conservation of Birds III   Student Paper