SPECIES SUMMARY PAGE

Asio otus - Long-eared owl:

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Summary Information
Living Organisms / Animalia / Craniata / Aves / Strigiformes / Strigidae / Asio / Species
Alternative Names
  • Ransuil (Dutch)
  • Hibou moyen-duc (French)
  • Waldohreule (German)
  • Gufo comune (Italian)
  • Bho chico (Spanish)
  • Hornuggla (Swedish)
Description Weight: Asio otus otus
  • Male: 220-330g (B162).
  • Female: 240-370g (B162).

Length: 35-37mm (B162); 31-37cm (B164); 36cm (B165).

Wingspan: 90-100cm (B162); 86-98cm (B164).

External Appearance: Long and slender vertical position when disturbed, but fluffed out when relaxed. Wings fairly long, head rather narrow. Long ear tufts, most visible when alert, least visible in flight.(B162, B163, B164).

  • Adult: Mixed browns and grey with fine markings.
  • Dorsal: Mixed grey and rufous-buff plumage with fine darker markings.
  • Ventral: Pale plumage with dark streaks over both breast and abdomen.
  • Wings: Flight feathers finely barred (4-5 bars), primaries having yellow-buff bases, (wing tip not black, no white trailing edge); primary coverts form dark patch. Underside flight feathers greyish with fine black bars including on wing tip, coverts more buff, primary coverts black tipped
  • Tail: upper surface buff, finely barred; under surface more grey, finely barred.
  • Face: Warm buff or rusty-buff, with black patches around eyes and pale whitish central dividing patch forming oblique "eyebrows". Eyes: orange (B162, B164); red (B165)
  • Feet: feathered, buff/whitish.
  • Female: darker on average than male , ventral more streaked, face darker buff (B164)
  • (B162, B164, B165)

 

Range and Habitat Western Palearctic, eastwards across southern Siberia and north-central Asia to Japan. Africa: locally in Ethiopia, Kenya, Zaire. North America. (B162).

Most of Britain, and Ireland (B165).

Accidental: Spitsbergen, Bear Island, Iceland, Iraq, Kuwait (B162).

Movement:

  • Northern populations (Fenno-Scandia and former Soviet Union north of 50N) mostly migratory.
  • Southerly populations resident or local movements.

(B162, B163, B164).

Habitat: Where trees and open ground in association: for feeding, open spaces with short ground vegetation; for breeding, various sized woodlands, particularly where conifer woods offer good availability of old nests (B162, B163, B164, B165).

Conservation: local declines in some areas of range (B163).

Further Information Food:
  • Small rodents (voles and mice, shrews).
  • Also birds, larger mammals.

(B162, B163, B164)

Feeding Behaviour:

  • Mainly nocturnal (diurnal also particularly when chicks in nest).
  • Generally hunts on the wing searching over open ground, flying at about 0.5-1.5m above ground and swooping onto prey.
  • Occasionally hovers.
  • Also hunts from perch.
  • (B162, B163)

Breeding:

  • Season: (Britain, north-west Europe, Scandinavia) from March, occasionally late February. (B162).
  • Broods: usually one, perhaps occasionally two (B162).
  • Nest: in old nest of e.g. magpies, crows, sometimes squirrels. sometimes scrape on ground - in thick vegetation or at tree base. Also in nest boxes. Little material added (B162, B163, B164).
  • Eggs: white, unmarked, smooth, slightly glossy, elliptical, 40mm long.(B162, B163).
  • Clutch: average 3-5, range 1-6 (B162, B163).
  • Incubation: 25-30 days (B162, B163).
  • Hatch: asynchronous (B163).
  • Chicks: semi-altricial (B163).
  • Fledging more than 30 days (B162, B163), however leave nest at 21-24 days (B162).

Breeding Behaviour:

Monogamous, with display flights, courtship-feeding and mutual preening (B163).

  • Nest built by female (B163).
  • Incubation: by female, with male bringing food (B163).
  • Chicks tended: by both parents, until several weeks after leaving nest (B163).

Activity:

  • Mainly nocturnal (B162, B163, B165); nocturnal and crepuscular (B164).
  • Upright when perching, often against tree trunk (B165).

Social Behaviour:

  • Territorial while breeding (B163).
  • Mainly solitary outside breeding season, but may congregate at roosts at sites of local food abundance.
  • Southern, non-migratory birds may remain as pairs on territories year-round.

(B162)

Organisations (UK Contacts):

Electronic Library (further reading):

General Legislation:

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Individual techniques:

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