干旱区生态环境知识资源中心

We examined diets of Western Burrowing Owls (Athene cunicularia hypugaea) based oil contents of pellets and large prey remains collected year-round at bill-rows ill each of the 3 regions in south central Nevada (Mojave Desert, Great Basin Desert, and Transition region). The most common prey items, based oil percent frequency of occurrence, were crickets and grasshoppers, beetles, rodents, Still spiders, and scorpions. The most common vertebrate prey was kangaroo rats (Dipodomys spp.). Trite bugs (Hemiptera), scorpions, and western harvest mice (Reithrodontomys megalotis) occurred most frequently in pellets from the Great Basin Desert region. Kangaroo rats (Dipodomys spp.) and pocket mice (Perognathinae) were the most important vertebrate prey items in the Transition and Mojava Desert regions, respectively. Frequency of occurrence of any invertebrate prey was high (>80%) in samples year-round but dropped in winter samples, with scorpions and sun Spiders exhibiting the steepest declines. Frequency of occurrence of any vertebrate prey peaked in spring samples, was intermediate for winter and summer samples, and was lowest in fill samples. With the possible exception of selecting for western harvest mice in the Great Basin Desert region, Western Burrowing Owls in our study appeared to be opportunistic foragers with a generalist feeding strategy.