While diets of Mexican Spotted Owls within forested habitat have been studied, little research has been published on the diet of owls that occupy canyon habitats (see Willey In Press). Since the Mexican Spotted Owl is federally listed as a threatened species, it is important to identify primary prey of Utah’s canyon dwelling owls to better understand their dietary needs (U.S. Fish and Wildlife Service 1993). We hope that the findings from this research can better inform state and federal managers on spotted owl prey use and aid in future management of small mammal populations in canyon habitats. We intend to compare our results with the findings of Willey (In Press) to determine whether any differences in diet exist. We will determine the time of day owls were foraging. A complete list of prey species will be compiled and the mean dietary composition will be computed for each owl territory. Mean biomass and frequency of prey captured at each site will also be calculated. Lastly, the evenness of the owl’s diet between study areas will be compared using the Simpson’s Index. Understanding the Mexican spotted owl’s prey base in canyon habitats will provide insights into potential population limiting factors
