Diet of Mexican spotted owls in Chihuahua and Aguascalientes, Mexico

We analyzed pellets of Mexican Spotted Owls (Strix occidentalis lucida) collected at roost and nest sites in Chihuahua from 1992-94, and Aguascalientes, Mexico from 1994-95 to determine diet composition. We identified 647 prey items from 13 owl territories in Chihuahua and four owl territories in Aguascalientes. Vertebrates constituted 64% of all prey items and 99% of total prey biomass. Woodrats (Neotoma spp.), mice (Peromyscus spp.) and cottontail rabbits (Sylvilagus floridanus) comprised 82% of total prey biomass in Chihuahua and 89% of total prey biomass in Aguascalientes