Comparing the diet of Great Horned Owls (Bubo virginianus) in rural and urban areas of southwestern British Columbia

Résumé

We investigated the diet of Great Horned Owls (Bubo virginianus) in southwestern British Columbia. Our objective was to compare the diets of owls in urban and rural areas and determine whether urban owls consume a higher proportion of commensal rodents to understand possible pathways of secondary rodenticide poisoning of Great Horned Owls. Among 546 prey items identified at seven sites, Townsend’s Vole (Microtus townsendii [Bachman, 1839]) and rats (Rattus G. Fischer, 1803) were the two main prey items, making up 65.9% and 13.1% of the diet, respectively. The proportion of rats in the diet was positively correlated with the degree of urban development in the owls’ home range (r_p = 0.83, P < 0.05, df = 5).