A study by Engel et al (2015) suggest that the Northern Saw-whet Owl’s diet may vary in the winter. On average, the owl’s diet consists mostly of small prey. Studies by Swengel and Swengel (1992) showed that Midwest owls preferred a diet of deer mice (Peromyscus) and shrew (Sorex cinereus and Blarina brevicauda). This contrasted to what was discovered in Chain O'Lakes State Park, Illinois, during the winter of 1987-88. At times, Northern Saw-whet owls may hunt larger prey, such as meadow vole (M. pennsylvanicus).[1]

  1. ^ Engel, J. I., Dubey, N., & Gnoske, T. P. (2015). Diet comparison of two wintering species of owl in the same stand of trees in Northern Illinois. Transactions of the Illinois State Academy of Science, 108(1), 17+.