Long-eared Owl

Asio otus (Asio: Latin, “A kind of horned owl; otus: Greek, “An eared owl.”)
Prepared by: 
Ann Walton
  • Length: 13 – 16 inches
  • Wingspan: 36 – 42 inches
  • Weight: male: 178 – 314 gm., female: 210 – 342 gm.

    
A slender owl with long, erect, and closely-set ear tufts.  Adult male and female similarly colored, but males are often paler than females.  Upperparts of eastern form (wilsonianus) is a blended brown and tawny, while the western form (tuftsi), with its mix of dusky and white, appears lighter and grayer.  Underparts of both subspecies are more boldly streaked and cross-hatched with the same blend of colors.  Wings show an inconspicuous buff patch at base of primaries, and a small black crescent below at “wrist.”  Facial disk is a bright rust in eastern form, and a light tawny color in the western race;  eyes of both forms are a yellow-orange, and bills are dark.  Juveniles are similar to adults, but often are more richly colored with some blackish brown barring.

 

Subspecies: 
Six recognized; only two subspecies in North America (A.o.wilsonianus in eastern NA; A.o.tuftsi in western N.A.)
Distribution: 
Temperate belt across North America, Eurasia, and northern Africa; also found in Canary Islands and Azores. In North America, their range extends across central Canada and south through US (including Bermuda) to central Mexico.
Habitat: 
Any kind of wooded country is used (forest patches in mountains, prairies, deserts, agricultural areas, and even in urban parks and gardens), as long as these wooded areas are adjacent to open fields or marshes. During the day, it roosts motionless in a tree, close to the trunk. In winter, dense evergreen forests or thickets are preferred, often roosting gregariously in large, close-knit groups. Also will use caves and rock crevices for winter roosts if forests are scarce.
Feeding: 
In North America, predominately feeds on small mammals (voles, mice, shrews); less than 2% of diet consists of birds, up to the size of grouse. Rarely feeds on small snakes, frogs, and beetles. Known to have killed screech and saw-whet owls. Hunting strictly at night, this long-winged owl, gliding low over open areas with a buoyant and moth-like flight, closely resembles a nocturnal harrier. When prey is sighted, the flight is suddenly stalled; the owl then drops down, with talons spread, pinning the victim to the ground.
Breeding: 
Mid March to July. Rarely builds own nest; uses any abandoned crow, squirrel, hawk, raven, and magpie nests that is 10 – 40 feet from the ground. Sometimes adds small sticks, inner bark strips, or pine needles, depending upon the condition of the old structures. Also is known to use shallow cavities in hollow trees or stumps, as well as holes in cliff faces. Occasionally will scrape out a nesting area on ground in dense thickets. Clutch is 3 – 8 eggs, usually 4 – 5. These owls are ready to breed after one year; long term pair bonding occurs where adults are sedentary.
Movements: 
Partial migrant. In winter, birds in northern part of range move south, while some inland birds move to coastal roosting locations. In regional areas where food supply remains constant, and the ground stays snow-free, adults are usually sedentary. Time of migration is weather dependent; spring movement takes place roughly from April to May, and fall migration extends from October to November.
Status: 
Fairly stable worldwide. Slow decline in Great Britain, and possibly in western US, because of habitat destruction.