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Southwest Adventure, Living & Travel


Long-Eared Owls

Asio otus

by Damian Fagan


Long ear owls

For several summers in the 1990s, I worked as a contract biologist surveying for Mexican Spotted Owls in the Southwest.  During those nocturnal surveys, I came across many different species of owls from Spotteds to Flammulateds.  One of my favorites, though, was the Long-eared Owl (Asio otus), whose deep hoots could be heard from far away.

 

Asio is the ancient Roman naturalist Pliny the Elder’s name for this genus.  Otus is also Latin and means “a kind of owl with long ear feathers,” hence the common name - Long-eared Owl.

Description

Long ear owlsThese owls are strictly nocturnal, but sometimes I would locate roosting individuals in the daylight.  Though their bodies and wings are grayish brown and their breasts are marked with dark streaking and barring, it would always be their yellow eyes set within an orangish facial disk edged in black that would betray their presence.  Their dark eye stripes were set off with white vertical lines in the center of their face.  The long ear tufts, which give the species its common name, are set closer together on the top of the head than those of the Great-horned Owl.

Range

The Long-eared Owl is a common resident throughout much of North America and Eurasia.  Their Eurasian range includes an area from Western Europe to North Africa to China and Japan.  Wintering birds may be found in Egypt, northern India and southern China.  In North America, this species is found from Canada to northern Mexico, and is an occasional winter visitor in the southeastern U. S. 

In the desert Southwest the Long-eared Owl inhabits a wide elevational range, from sea level to 9,000 feet.  The owls occur in juniper woodlands and coniferous or deciduous forests at higher elevations.  The owls may also nest in riparian woodlands, parks, shelterbreaks along agricultural fields, or orchards.  Sometimes the owls will nest in loose colonies, but this is a function determined by prey abundance.  In winter, communal roosts may have five or six birds, but up to 60 have been recorded. 

Long ear owls

Habitat

Though Long-eareds roost in dense thickets, they prefer to hunt in openings and fields.  They hunt by perching and pouncing on prey or by coursing low over fields searching for small mammals where they locate prey by sound or sight. 

Their prey consists primarily of small mammals from mice to voles, but they will take small rabbits, shrews, rats, snakes, and small birds opportunistically.  Studies of their pellets, regurgitated wads of fur and bones, may reveal small mammal species that are overlooked in small mammal trapping surveys.  I guess this means that the owls are more proficient than some small mammal traps at sampling the local rodent populations.

Adult Long-eareds have similar plumage, but females are a bit larger than males.  Average weights for a female is about 10 ounces, while males average about 8.5 ounces.  Wingspans vary from 36 to 42 inches and body length ranges from 13 to 16 inches. 

Life Cycle

These owls tend to be long-lived.  One banded individual (from Germany) was 27 years and 9 months old at death.  Their life expectancy is between 25 and 30 years of age.  Adults or juveniles may be preyed on by Great-horned and Barred Owls, Golden Eagles, Red-tailed Hawks and Northern Goshawks.

During the courtship phase of the breeding season the male owl will fly in an erratic zigzag patterns with deep, slow wingbeats.  At times the male will “clap” his wings together beneath his body to attract the attention of a mate.  He will also present the female with food, an activity called “courtship feeding,” to establish his abilities to successfully hunt.  This will be an important role later on for the male during the incubation phase. 

During the breeding season, between February and July, Long-eareds will lay an average of five to seven white eggs in an abandoned magpie, crow, raven, squirrel or hawk nest.  Occasionally the owl will build its own nest or use a topped tree for a nest site.  Ground nests have been observed, but this seems rare. 

The female is the primary incubator and, depending upon the source, will be spelled by the male for short periods of time or leave the eggs only for a short break at night.  The male will provide the female with food during this time.  The eggs take an average of 26 to 28 days to hatch.  Three weeks after hatching, the young will leave the nest and move out onto branches surrounding the nest.  The young cannot fly for another two weeks, but during this time the male and female will feed the young.  The male will continue to feed the young owls until they are about 10 to 11 weeks old, prior to their dispersal from the natal area.

Though predators themselves, the young have been known to fall prey to several species of hawks as well as American Crows, Black-billed Magpies, and tree climbing bull snakes.  When predators approach too close to a Long-eared nest, the adults may dive-bomb the intruder while shrieking out alarm calls.  They may also defend their eggs or young by snapping their bills and spreading their wings behind themselves to appear larger than they really are.  The adults may even feign an injury like a broken wing to lure a predator away from their nest. 

Sometimes a disturbed bird will stretch its body upright and raise its ear tufts to resemble a stout limb and attempt to blend into its surroundings.  The adults may also emit a variety of calls from low moans to catlike wails (these birds were once known as cat owls due to these calls) to whines that sound like a litter of puppies.  These owls are generally silent during the non-breeding season.

Long ear owls

In flight, this owl’s long wings make its flight appear buoyant like a moth.  The lighter undersides of the wings show off a dark comma at the wrist.  This field mark is similar to the one on their close relative, the Short-eared Owl.  However, those owls are more diurnal in their activities, have barely noticeable ear tufts, and have different plumage.


 

 


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