Overview
AT A GLANCE
- Common Name: Short-eared Owl
- Scientific Name: Asio flammeus
- Category: Birds
- Subcategory: Owls
- Size: 34 to 43 cm (13.4 to 16.9 in) length; 85 to 110 cm (33.5 to 43.3 in) wingspan
- Weight: 205 to 475 g (7.2 to 16.8 oz)
- Lifespan: 10 to 15 years in the wild; up to 21 years in captivity
- Diet: Carnivorous specialist; primarily microtine voles, lemmings, mice, shrews, and small grassland birds
- Habitat: Vast open expanses of treeless grasslands, coastal saltmarshes, and prairie swales
- Range: Nearly worldwide distribution; breeds across North America, Eurasia, South America, and oceanic islands including Hawaii, wintering south across temperate and subtropical latitudes
- Conservation Status: Least Concern
The Short-eared Owl (Asio flammeus) is an exceptionally wide-ranging, nomadic raptor belonging to the family Strigidae, possessing one of the most extensive geographic distributions of any bird on Earth. Unlike most strictly nocturnal strigids, this graceful grassland hunter is regularly active during daylight and crepuscular hours, captivating naturalists with its buoyant, moth-like wavering flight over vast open marshes, tundra plains, and coastal prairies.
In open-country ecosystems across the globe, the Short-eared Owl serves as an essential demographic regulator of cyclic small mammal populations, particularly microtine voles and lemmings. It is one of the few owl species that nests directly upon the ground, concealing its scrapes within tall prairie grasses or heather. Highly nomadic, populations track rodent boom-and-bust cycles across continents, congregating in large numbers where prey is abundant and abandoning barren regions.
Biology and Physical Characteristics
Asio flammeus features a streamlined, medium-sized body covered in tawny-buff plumage boldly streaked with dark brown on the breast and back. Its facial disc is remarkably round and pale, highlighted by intense, piercing sulfur-yellow eyes set within striking dark soot-black eye patches that create a fierce, alert glare. Its eponymous ‘short ears’ are tiny, inconspicuous feather tufts located above the center of the forehead, usually kept flattened against the skull and raised only during courtship or threat displays. In flight, its unusually long, narrow wings reveal a distinct dark comma-shaped mark at the wrist (carpal joint) on the pale underwing. Its acoustic system features vertically displaced ear openings that facilitate microsecond auditory triangulation of scurrying rodents beneath tall grass.
Behavior and Ecology
Hunting primarily on the wing, the Short-eared Owl flies low over open vegetation with deep, stiff, buoyant wingbeats punctuated by graceful glides, resembling a giant moth quartering the fields. When a vole is detected via sound or sight, it hovers momentarily before dropping feet-first into the grass to seize the prey with razor-sharp talons. Courtship displays in early spring involve dramatic sky-dancing by the male, soaring high above the prairie before executing steep dives accompanied by audible ‘wing-clapping’ produced by slapping the primary flight feathers together beneath the body. Females lay clutches of 4 to 10 eggs in a shallow ground depression lined with grass and down.
Conservation and Human Impact
Assessed globally as Least Concern by the IUCN on account of its vast global range, the Short-eared Owl is nevertheless experiencing severe, documented regional population declines across North America and Western Europe. Ground-nesting exposes eggs and chicks to high predation from domestic dogs, cats, and foxes, while the widespread conversion of native tallgrass prairies and coastal marshes to intensive arable cropland and development has eliminated extensive contiguous hunting territories.
Interesting Factoid
During aerial courtship displays, male Short-eared Owls perform an astonishing ‘wing-clap,’ diving toward the earth and clapping their long wings together beneath their bodies at high speed to produce a loud, whip-like acoustic display.