Asio flammeus
California Department of Fish and Game "Species of Special Concern"
Life History
The short-eared owl is a bird of open country that is often seen during the day. It
exhibits a type of moth-like or irregular flapping flight. This owl is 13 to 17 inches in length,
about crow-sized. The coloration is a streaked tawny brown with the belly paler and more
lightly streaked. Large buffy wing patches are shown in flight and on the underwing, along
with a black wrist patch. A dark facial disk emphasizes the yellow eyes while the ear tufts are
barely visible in flight or on perched birds.
The short-eared owl will usually nest on dry ground in a depression that is concealed in
vegetation; occasionally the nest will be placed in a burrow. The nest is lined with grasses,
forbs, sticks, and feathers. Breeding is from early March through July with a
clutch size of usually five to seven eggs but as many as 14 have been recorded in years of high
prey availability. Incubation lasts 21 to 28 days with the male bringing food to the female and
the young after they have hatched. The young fledge at 31 to 36 days.
The short-eared owl was formerly a resident throughout the state, excluding the higher
mountains. They are usually found in open areas with few trees such as annual and perennial
grasslands, prairies, meadows, dunes, irrigated lands, and saline and fresh emergent marshes.
This owl requires dense vegetation for roosting and resting cover. This includes tall
grasses, brush, ditches, and wetlands. Open, treeless areas containing elevated sites for
perching are also needed.
The short-eared owl is a widespread winter migrant that is found primarily in the
Central Valley and the western Sierra Nevada foothills. Migrants usually arrive in California
in September and October and depart in April.
California voles, Microtus californicus, are the preferred prey species for the short-eared owl in the Central Valley grasslands. Other small mammals are taken
along with marsh birds, insects, reptiles, and amphibians. They will frequently search for
prey items in low, gliding flights of 3 to 20 feet above the ground. They can often be
identified at a great distance by their habit of hovering. They will swoop and pounce and also
commonly hunt from a fence post or mound where they have been perched motionless.
Numbers have declined over most of the range in recent decades because of destruction
and fragmentation of grasslands and riparian habitats. This fragmentation of
habitats is disruptive for the necessary cover and hunting requirements.
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