Helminth Parasites of the Black-Billed Magpie, Pica pica hudsonia (Sabine, 1823), from Southwestern Montana

Helminths recovered from 25 nestlings, 65 juvenile, and 55 adult black-billed magpies, Pica pica hudsonia (Sabine, 1823) between April 1963 and April 1964, were Echinostoma sp., Dilepis undula, Hymenolepis stylosa, Aploparaksis picae, Hymenolepis sp., Anomotaenia constricta, Capillaria anatis, Syngamus trachea, Acuaria sp., and Microtetrameres corax. Echinostoma sp., Aploparaksis picae, Acuaria sp., and Microtetrameres corax are new host records. Capillaria anatis has not been previously reported from the magpie in the United States. Helminths were found in all juveniles, in 32% of the nestlings, and 98.2% of the adults examined. A 13-day-old bird was the youngest to harbor worms. Incidence of infection was similar in juvenile and adult birds although the mean total number of helminths was higher until January in the former.