Long-eared Owl

Asio otus

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

Length: 13-15 in. (male); 14.5-16 in. (female)
Weight: 8-11 oz. (male); 9-15 oz. (female)
Wingspan: 36-42 in.

Common Names: cat owl

Etymology: asio (Latin) - "a kind of horned owl"; otus (Latin) - "a horned or eared owl"

Description: A medium-sized owl with legs and toes densely feathered. Head large and round with conspicuous "ear" tufts and a round facial disk. Yellow to golden yellow or orange eyes. Wings are long and rounded with 10 functional primaries. Facial disk buff with white "eyebrows" and white patch below bill; lores and bill black. Males are generally paler than females, especially facial disk, tarsi, and underwing coverts. Overall, female plumage tends to have more dark brown and richer buff.

Flight: Wing beats fast, interrupted by short glides. Hunting flight consists of long glides on level wings interrupted by deep wing beats. Often pulls up and hovers over prey. Extremely agile, using quick twists and turns when flying through dense vegetation. Light wing loading.

Voice: Complex vocal repertoire in breeding season, but mostly silent at other times. Alarm calls variable and given by both sexes. Most common is barking ooack ooack ooack. Call is higher pitched in females than in males, presumably owing to smaller syrinx of females.

Habitat: The long-eared owl inhabits open and sparsely forested habitats across North America and Eurasia between 30 and 65 N latitude. Inhabits dense vegetation adjacent to grasslands or shrublands; also open forests.

Distribution: Canada; south to north Baja California, southern Arizona, southern New Mexico, east to Pennsylvania, New York, and northern New England.

Nesting: Male performs courtship flights over suitable nesting habitat. Female sits in potential nests shortly before laying and thus probably selects nest site. Typical site is stick nest built in tree by another species of bird (magpie, crow, and ravens). In general, no material added to nest lining. Lays 2-10 (usually 5-6) eggs. Incubation by female only, normally lasts 26-28 days. Male feeds female throughout incubation. Owlets leave nest at 21 days old and are about 35 days old when owlets begin making short flights. During branching period, male made 2.5 times more food deliveries than did female. Female fed young until deserting when young were 6.5-8 weeks old; male continued to provision young for 2-3 weeks after female deserted.

Food: Typically hunts on wing over open ground, coursing back and forth .5-2 meters above ground; occasionally hovers. May hunt from perch. Mostly nocturnal. Kills small mammals by biting back of skull. Often swallows prey whole. Can capture mice in complete darkness. External ear openings asymmetrical and large. Major food items: voles, deer mice, pocket gophers, shrews, juvenile rabbits, juvenile rats, and passerine birds.