Adult Splendidofilaria caperata Hibler, 1964 were found in the tunica media of the pulmonary arteries of 21% of 341 crows (Corvus brachyrhynchos brachyrhynchos Brehm) wintering in southern Ontario, Canada. Microfilariae of S. caperata were not observed in the peripheral blood or in skin snips of infected crows. Microfilariae were rarely found in lung blood and then only in small numbers. Microfilariae were apparently overcome in the wall of the pulmonary artery; chronic inflammation was associated with their presence in arterial tissue. Crows apparently acquire S. caperata from insects that have fed on birds in which a microfilaraemia does develop.