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long-eared owl

Asio otus

What do they look like?

Long-eared owls are medium-sized owls. They have long, rounded wings and a long tail. The wings are so long that they cross each other in the back when the bird is perched. The wingspan of adults ranges from 90 to 100 cm. Long-eared owls are brownish gray, with vertical streaks. They have pale patches on their face that look like eyebrows, and a white patch below the bill. They have a black bill, orange or yellow eyes, and their legs and toes are covered with feathers. Long-eared owls have long blackish tufts that look like ears, but are really just feathers.

Female long-eared owls are usually much larger than males. Females weigh 260 to 435 g and are 27 to 40 cm long. Males weigh 220 to 305 g and are 35 to 37.5 cm long. Females are also darker than males. Young long-eared owls look like adults, but have softer, looser feathers.

Long-eared owls are the slimmest of all North American owls. This shape helps them hide from predators. When they are perched, long-eared owls stretch out their body flatten their feathers to make themselves look like a tree limb.

  • Sexual Dimorphism
  • female larger
  • sexes colored or patterned differently
  • Range mass
    220 to 435 g
    7.75 to 15.33 oz
  • Range length
    35 to 40 cm
    13.78 to 15.75 in
  • Range wingspan
    90 to 100 cm
    35.43 to 39.37 in
  • Average basal metabolic rate
    0.954 W
    AnAge

Where do they live?

Long-eared owls are found throughout the northern hemisphere. Their range extends throughout temperate North America, through Europe and the former Soviet Union as far east as Japan. Isolated populations are also found North and East Africa, the Azores, and the Canary Islands.

What kind of habitat do they need?

Long-eared owls live in forests and shrub lands that are near to open areas, such as grasslands. They can be found from sea level up to 2000 m elevation. They are common in tree belts along streams in dry habitats. They can also be found in shelterbelts, small tree groves, thickets surrounded by wetlands, grasslands, marshes and farmlands.

  • Range elevation
    0 to 2000 m
    0.00 to 6561.68 ft

How do they reproduce?

Long-eared owls are monogamous. Pairs begin to form in winter, and they breed between February and mid-July. Males attract a female by singing songs and showing off their flying skills.

Long-eared owls breed between February and July. They raise one brood per season. Long-eared owls nest in trees in nests built by other species. Once they choose a nest, the female lays 2 to 10 (usually 5 to 6) eggs. She lays one egg every other day. The eggs are white, smooth and glossy. The female incubates the eggs for 25 to 30 (usually 26-28) days. She never leaves the eggs uncovered during the day, but she takes short breaks at night. The chicks are semi-altricial. The female broods them for at least 2 weeks. The young leave the nest when they are about 21 days old, but they cannot fly yet. They leave the nest by walking, and live on branches near the nest. They begin flying when they are about 35 days old. The male brings food for the female and chicks until the chicks become independent. This happens when they are 10 to 11 weeks old. Long-eared owls usually begin breeding at 1 year.

  • How often does reproduction occur?
    Long-eared owls breed once yearly.
  • Breeding season
    Long-eared owls breed between February and July.
  • Range eggs per season
    2 to 10
  • Average eggs per season
    5-6
  • Average eggs per season
    4
    AnAge
  • Range time to hatching
    25 to 30 days
  • Average time to hatching
    26-28 days
  • Average fledging age
    21 days
  • Average time to independence
    8-9 weeks
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

Female long-eared owls incubate the eggs and brood the semi-altricial chicks for at least two weeks. During incubation and brood rearing, the male provides food for the female and chicks. The male continues to feed the chicks until they become independent at 10 to 11 weeks old.

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • male
    • protecting
      • female
  • pre-independence
    • provisioning
      • male

How long do they live?

The oldest wild long-eared owl lived 27 years and 9 months.

How do they behave?

Long-eared owls are nocturnal. They live in pairs during the breeding season, but may roost together in small groups during the winter. Long-eared owls are not territorial. They defend only the area right around their nest. Nests may be as close to each other as 14 m.

Some long-eared owls are migratory. Others stay in the same area year-round. Other long-eared owls are nomadic. These owls move around throughout the year to find better food supplies.

Home Range

The home range size of long-eared owls is between 0.7 and 20.25 square kilometers. The home range size is probably very different for different pairs and changes between winter and summer.

How do they communicate with each other?

Long-eared owls use calls and displays to communicate. They have many calls that they use during the breeding season. During the rest of the year, they are mostly silent. The most common calls are soft musical hoots and single quavering hoots. When excited, long-eared owls may also shriek or whistle. When chicks are threatened, parents use calls to scare away the predator. They may also pretend to be crippled to distract the predator from the nest. Long-eared owls use threat displays when disturbed by humans or predators. They don’t usually threaten each other.

Long-eared owls have excellent hearing and vision. These senses help them to be excellent hunters.

What do they eat?

Long-eared owls hunt at night in open habitats. They have excellent eyesight and hearing that they use to catch prey.

Long-eared owls eat small mammals, including voles, deer mice, pocket mice, kangaroo rats, pocket gophers, shrews (genera Glarina, Cryptotis and .Sorex), juvenile rabbits (genera Sylvilagus and Lepus) and juvenile rats. They also eat some small birds, small snakes, and insects. After they catch prey, long-eared owls kill it by biting the back of the skull and then they swallow it whole. They store extra food in the nest during incubation and while chicks are in the nest. We do not know how long-eared owls drink water.

  • Primary Diet
  • carnivore
    • eats terrestrial vertebrates
  • Animal Foods
  • birds
  • mammals
  • reptiles
  • insects

What eats them and how do they avoid being eaten?

Adult long-eared owls are preyed upon by many other raptors. Raptors that have been observed taking long-eared owls include great-horned owls, barred owls, golden eagles, red-tailed hawks, red-shouldered hawks, northern goshawks, eagle owls, common buzzards, and peregrine falcons. Incubating female long-eared owls have been killed by raccoons.

Long-eared owl nestlings are vulnerable to predation by porcupines, bull snakes, American crows, black-billed magpies, and several hawk species.

Roosting adults are difficult to see because their coloration, slender body and ear tufts help them to look like a branch of the tree that they are roosting in. When a predator approaches a nest, adult long-eared owls defend the eggs or young by circling the nest and snapping their bill at the predator, or dive-bombing the predator while making alarm calls. They may also pretend to be injured in order to draw the predator away from the nest. In some cases, adults from several nearby nests may all perform defense displays when a single nest is threatened.

  • These animal colors help protect them
  • cryptic

What roles do they have in the ecosystem?

Long-eared owls affect the populations of animals they eat. They also provide habitat for many external and internal parasites.

Do they cause problems?

Long-eared owls have no known negative effect on humans.

How do they interact with us?

Long-eared owls help to control populations of rodents that are considered to be agricultural pests.

  • Ways that people benefit from these animals:
  • controls pest population

Are they endangered?

Long-eared owl populations in the United States are healthy. Most long-eared owl deaths are probably caused by starvation or predation. Adult long-eared owls are sometimes killed by cars or shot by hunters in the U.S., but this is not common.

Long-eared owls are protected under CITES Appendix II and the U.S. Migratory Bird Act. They are not federally endangered or threatened in the United States, but they are considered threatened in the state of Michigan.

Some more information...

There are six subspecies of long-eared owls (Asio otus).

Contributors

Kari Kirschbaum (author, editor), Animal Diversity Web.

Alicia Ivory (author), University of Michigan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.

carnivore

an animal that mainly eats meat

chaparral

mid-altitude coastal areas with mild, rainy winters and long, dry summers. Dominant plant types are dense, evergreen shrubs.

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

endothermic

animals that generate their own body heat through metabolic processes.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

holarctic

World Map

Found in northern North America and northern Europe or Asia.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

migratory

makes seasonal movements between breeding and wintering grounds

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

nomadic

generally wanders from place to place, usually within a well-defined range.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

stores or caches food

places a food item in a special place to be eaten later. Also called "hoarding"

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical savanna and grassland
savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland
visual

uses sight to communicate

References

Marks, J.S., D.L. Evans, and D.W. Holt. 1994. Long-eared owl (Asio otus). In The Birds of North America, No. 133 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists' Union.

Terres, J. The Audubon Society Encyclopedia of North American Birds. Alfred A. Knopf, New York, 1980.

"The Raptor Center; University of Minnesota College of Veterinary Medicine" (On-line). Accessed (Date Unknown) at http://www.ahc.umn.edu/ahc_content/colleges/vetmed/Depts_and_Centers/Raptor_Center/index2.cfm/nav/9773/parent/9748/type/F/content_path/colleges@vetmed@Depts_and_Centers@Raptor_Center@Information_about_Raptors/content_name/Long-eared_Owl.htm/pic/none/bold/Information_about_Raptors.

 
University of Michigan Museum of ZoologyNational Science Foundation

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Ivory, A. 1999. "Asio otus" (On-line), Animal Diversity Web. Accessed April 20, 2014 at http://www.biokids.umich.edu/accounts/Asio_otus/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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