Prey remains are described from a 4-month accumulation of pellets from a nesting pair of barn owls. Of 233 individual prey items, 163 (73.1%) were microtines, primarily prairie voles and pine voles. The minimum estimated daily mean biomass consumed by each owl was 49.8 g per day.
Feldhamer, George A. "Summer Feeding Habits of Barn Owls (Tyto alba) from White County, Illinois." (Jan 1985).