Helminths in the great horned owl, Bubo virginianus, and snowy owl, Nyctea scandiaca, of Alberta.

A total of 69 great horned owls (Bubo virginianus) and 16 snowy owls (Nyctea scandiaca) collected in Alberta from 1971 to 1974 were examined for helminths. Fourteen and four species of helminths were found in the host species, respectively. Echinoparyphium recurvatum, Echinostoma revolutum, Notocotylus attenuatus, Hysteromorpha sp., Capillaria falconis, and Cyrnea americanum are new records for great horned owls; Cyrnea longispicula is new for snowy owls. Many of the species recovered were probably acquired on the nonoverlapping summer ranges of each host.