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

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).