Northern Saw-whet Owls (Aegolius acadicus) are one of the smallest owl species in North America (Length: 7.1-8.3 in; Weight: 2.3-5.3 oz; Wingspan: 16.5-18.9 in.).
Northern Saw-whet Owls are forest birds. They breed in extensive forests across northern North America, also sometimes using more open habitats such as the shrubsteppe of the West as long as there are nest sites available. They winter in dense forests across the central and southern U.S.
They are nocturnal and hard to see, but they have a shrill, penetrating call that they give many times in succession.
The northern saw-whet owl’s hearing is very sophisticated, due to vertically asymmetrical ears and different shape of the ear openings. Because the sound reaches the ears at a different time and is of different intensity, the northern saw-whet owl can very precisely localize its prey. Such accurate sound localization allows it to hunt in a complete darkness by hearing alone. (Diet includes mostly small rodents / mice that live in forest, especially deer mice; also many voles.)