Northern Saw-whet Owl

The Northern Saw-whet Owl, Aegolius acadicus, is a diminutive and elusive bird of prey, belonging to the family Strigidae. This species, one of the smallest owls in North America, is distinguished by its lack of ear tufts and a round, white face with brown and cream streaks. It possesses a dark beak, captivating yellow eyes, and a body size comparable to the American robin. The underparts are pale with dark shaded areas, while the upper parts are a rich brown or reddish hue adorned with white spots.

Identification Tips

To identify the Northern Saw-whet Owl, look for its small stature, typically ranging from 17 to 22 cm in length with a wingspan of 42 to 56.3 cm. The females are slightly larger than the males, averaging around 100 g, while males average 75 g. Juveniles can be recognized by their dark brown head and wings, contrasted with a tawny rust-colored breast and belly, and a distinctive white, Y-shaped mark between their eyes.

Habitat

These owls favor coniferous forests, often mixed or deciduous, across North America. They are known to nest in tree cavities and old nests made by other small raptors, and they show a particular fondness for riparian areas due to the abundance of prey.

Distribution

The Northern Saw-whet Owl's range extends across most of North America, from southeastern and southcentral Alaska, through southern Canada, the majority of the United States, and into the central mountains of Mexico. Some populations are permanent residents, while others migrate or move to lower elevations during winter.

Behaviour

This species is migratory, though not following a strict pattern. They are primarily nocturnal and can be preyed upon by larger raptors. During the breeding season, males may sing from a nest site and cache food to attract females.

Song & Calls

The Northern Saw-whet Owl is known for its tooting whistle, likened to the sound of a saw being sharpened on a whetstone. These calls are most commonly heard during the breeding season from April to June. The owl has a repertoire of at least 11 different vocalizations, including the Advertising call, Rapid call, Whine, and various non-vocal sounds like bill snapping.

Breeding

The breeding behavior of the Northern Saw-whet Owl involves laying four to six white eggs in natural tree cavities or woodpecker holes. The species practices sequential polyandry, where the female may have multiple clutches with different males in a single season. They face competition for nesting sites and predation from various species.

Similar Species

Juvenile Northern Saw-whet Owls can be confused with juvenile Boreal Owls. The species also resembles the Short-eared Owl but is much smaller in size.

Diet and Feeding

These owls have a diet focused on small mammals, particularly rodents such as deer mice and voles. They are capable of hunting in complete darkness by using their acute hearing to localize prey. Their diet may also include small birds, crustaceans, frogs, and aquatic insects.

Conservation status

The Northern Saw-whet Owl is currently listed as Least Concern by the IUCN. However, some populations, particularly in the Southern Appalachians, are considered threatened due to habitat loss.