The Northern Saw-whet owl (Aegolius acadicus) is a very small, earless, yellow-eyed owl, brown above, streaked with white and rufous below. Usually silent, in later winter and spring the Saw-whet owl utters a monotonous series of whistles. Saw-whet owls are almost entirely nocturnal, spending the day roosting quietly in dense foliage. At such times they are extraordinarily tame and may be approached closely or even handled. At night this tiny owl becomes a rapacious hunter, preying on mice and other small rodents. Thanks to its huge asymmetrical ear cavities, this species has remarkable hearing. They are preyed on by barred owls and great horned owls.
On average, Northern Saw-whet owls are about 8 inches in length and have wingspan of about 20 inches. Thick feathers extend down on their feet, and due to their relatively short legs, they look a bit legless.
The female lays five or six eggs in an abandoned woodpecker hole, squirrel dens, hollow trees and stumps or artificial nest box. She sits on her eggs for about a month, then broods her nestlings for three weeks, while the male provides food consisting of deer mice, small birds and insects. The young leave the nest after four to five weeks. They close to the nest and are fed mainly by the male for another month or longer. The female may seek another male and raise another brood.
Saw-whet owls are quite tame and may nest on the edges or yards and towns.
- Fifty Uncommon Birds of the Upper Midwest. Dana Gardner, Nancy Overcott
- Wildlife of Pennsylvania and the Northeast. Charles Fergus, Amelia Hansen