Short-eared Owl

Asio flammeus

Taxonomy:
Class: Aves
Order: Strigiformes
Family: Strigidae
Subfamily: Striginae
Genus: Asio

Length: 13-17 in.
Weight: 6-18 oz. (females slightly larger than males)
Wingspan: 40-44 in.

Common Names: evening owl, grass owl, meadow owl, marsh owl, mouse-hawk

Etymology: asio (Latin) - "a kind of horned owl"; flammeus (Latin) - "flame-colored"

Description: Short-eared owls have a large and round head with very small tufts arising from the center of the forehead, generally not seen. Their face is large and the facial ruff is round during normal posture. Short-eared owls have a gray/white facial disk, yellow eyes and a black bill.

Flight: In ascending flight, bouncing high flapping wing-beats. When hunting, short-eared owls use few wing-beats interspersed with quartering on slightly positive dihedral wings. Their foraging flight is moth-like and buoyant with slow, deliberate wing beats. Low wing loading allows for slow, agile, maneuverable flight. Aerial agility a good field characteristic of this species as it is often seen foraging during the day. Short-eared owls hunt primarily on the wing, low to the ground, and also by hovering 2-30 m above ground or, less frequently, perched on poles or hills. Course area like northern harriers and quickly adjust their flight to drop down on prey. Short-eared owl display and courtship flight will include wing clapping.

Voice: Generally silent, don't use vocalizations much due to open habitat. Female give cuk call similar to a chicken when calling nestlings back to the nest.

Habitat: Almost always associated with open country supporting cyclic small mammals, typically large expanses of prairie and coastal grasslands, heathlands, shrub-steppe, and tundra. Short-eared owls winter in conifers and will roost communally with long-eared owls. One of the world's most widely distributed owls, the short-eared owl is an open country, ground nesting species that inhabits marshes, grasslands, and tundra throughout much of North America and Eurasia.

Distribution: Short-eared owls show patchy and irregular distribution in some areas, and they can be nomadic and occur in suitable open country where prey species are abundant. In North America, they are generally found year-round in the upper half of the United States and breed in Canada. Short-eared owls are migratory, and will move to the southern half of the United States and Central America.

Nesting: Short-eared owls are ground nesters; their nests are usually located on dry sites with enough vegetation to conceal the incubating female. Nest bowls scraped out by female and lined with grasses and downy feathers, and they will nest on ridges or mounds. Clutch size ranges from 1-11 (5.6 mean) and increases significantly with latitude. Incubation is done by the female only and lasts for 21-37 days. The female sometimes flips the eggs out of the nest when frightened or flushed. The female will retrieve the eggs that roll out of the nest by hooking her bill under each egg and rolling it back to the nest. Young owlets fledge from nests when they are about 24-27 days old.

Food: These owls are small mammal eaters, particularly Microtus voles. Other species include: shrews, moles, rabbits, pocket gophers, pocket mice, kangaroo rats, harvest mice, deer mice, voles, lemmings. Active day and night, this owl tends to hunt low above the ground, often quartering an area on slightly dihedral wings or hovering. Although it generally uses acoustical cues to locate prey (its ear openings are very asymmetrical), it can rely on vision as well.