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barn owl

Tyto alba

What do they look like?

Barn owls are medium-sized owls with long legs that have feathers all the way down to their grey toes. They have large, round heads without ear tufts. Barn owls have rounded wings and a short tail that is covered with white or light-brown, downy feathers. They have a light brown spotted head and back, and a light grayish belly. Females are larger than males. They weigh 570 grams, while males weigh around 470 grams. Females also have a slightly longer body length (34 to 40 cm for females, 32 to 38 cm for males) and wingspan than males. The wingspan of barn owls ranges from 107 to 110 cm.

There are up to 35 subspecies of barn owls. These subspecies are different from each other in size and color. ("The Owl Pages", 2003; Marti, 1992)

  • Sexual Dimorphism
  • female larger
  • Range mass
    430 to 620 g
    15.15 to 21.85 oz
  • Range length
    32 to 40 cm
    12.60 to 15.75 in
  • Range wingspan
    107 to 110 cm
    42.13 to 43.31 in

Where do they live?

Barn owls are the most widespread of all owl species, and are found on every continent except Antarctica. In the Americas, barn owls occur in suitable habitat throughout South and Central America, and in North America as far north as the northern United States and southwestern British Columbia. In Europe, barn owls range from southern Spain to southern Sweden and east to Russia. They are also found throughout Africa, across central and southern Asia, and throughout Australia. Barn owls have been introduced to some oceanic islands to control rodent pests.

What kind of habitat do they need?

Barn owls are found in a variety of habitats from cities to rural areas. They are usually found at low elevations in open habitats, such as grasslands, deserts, marshes and agricultural fields. They need cavities for nesting, such as hollow trees, cavities in cliffs and riverbanks, nest boxes, caves, church steeples, barn lofts, and hay stacks. (Marti, 1992)

How do they reproduce?

Barn owls are monogamous. Mated pairs usually stay together as long as both owls are alive.

Courtship begins with display flights by males which are accompanied by advertising calls and chasing the female. During the chase, both the male and the female screech. The male will also hover with feet dangling in front of the perched female for several seconds; these are known as moth flights.

Barn owls breed once per year. They can breed almost any time of the year, depending upon the food supply. Most barn owls first breed when they are 1 year old. Most barn owls raise one brood per year, but some pairs have raised up to three broods in one year

Barn owl pairs often use an old nest instead of building a new one. The female lines the nest with shredded pellets to make a soft surface for the eggs. She lays 2 to 18 eggs (usually 4 to 7). The female incubates the eggs for 29 to 34 days. The chicks are altricial, and must be brooded by the female for about 25 days after hatching. They leave the nest on their first flight 50 to 70 days after hatching, but they return to the nest to roost for 7 to 8 weeks. The chicks usually become independent from the parents 3 to 5 weeks after they begin flying. (Marti, 1992)

  • How often does reproduction occur?
    Barn owls breed once yearly; somtimes two or even three broods per year are produced.
  • Breeding season
    Barn owls breed essentially any time of the year, depending upon food supply.
  • Range eggs per season
    2 to 18
  • Average eggs per season
    5.5
  • Average eggs per season
    6
    AnAge
  • Range time to hatching
    29 to 34 days
  • Range fledging age
    50 to 70 days
  • Average fledging age
    64.3 days
  • Range time to independence
    3 to 5 weeks
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

Female barn owls incubate the eggs and brood the chicks until the oldest chick is about 25 days old. The male brings food to the female and the chicks. The female tears up the food to feed it to the chicks. The female also keeps the nest clean by eats the feces of the chicks for the first few weeks after they hatch. The parents feed the chicks for up to 5 weeks after they fledge. (Marti, 1992)

  • Parental Investment
  • no parental involvement
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • male
      • female
    • protecting
      • male
      • female

How long do they live?

Most barn owls do not live very long. Many only survive one breeding season. However, some individuals do live for many years. The oldest wild barn owl lived 34 years. (Marti, 1992)

  • Range lifespan
    Status: wild
    34 (high) years
  • Average lifespan
    Status: wild
    20.9 months
  • Average lifespan
    Status: wild
    185 months
    Bird Banding Laboratory

How do they behave?

Barn owls are solitary, or found in pairs. They are nocturnal, and roost during the day in tree cavities, cliff crevices, riverbanks, barns, nest boxes, churches steeples, and other man-made structures.

Barn owls are very efficient hunters. It is suspected that they spend much of their time loafing. Most barn owls are sedentary, though some individuals in the northern part of the range are migratory. (Marti, 1992)

Home Range

In a study of barn owls in New Jersey, the average home range was 7.17 square kilometers. (Marti, 1992)

How do they communicate with each other?

Barn owls communicate with vocalizations and physical displays. Owl chicks in the nest make several different calls. Chicks use a “twitter” call to express discomfort, to seek attention, and when quarreling with other chicks in the nest. They also give a raspy snoring food call.

Adults use a variety of vocalizations. Their common drawn-out gargling scream is an advertising call. They also use twitters to greet their mate and during courtship activities. Barn owls are vocal while breeding, but quiet during the rest of the year.

Barn owls have an amazing ability to locate prey by sound. They are better at this than any other animal that has been tested. Barn owls are so good at finding prey by hearing, that they capture prey that is hidden under vegetation or snow. Their ears are extremely sensitive and can be closed by small feathered flaps if the noise level is too loud. Barn owls also have excellent vision for seeing at night.

What do they eat?

Barn owls hunt small mammals such as mice, voles, shrews, rats, muskrats, hares and rabbits. They may also prey on small birds.

Barn owls begin hunting alone after sunset. They have excellent eyesight in near-darkness. When it is completely dark, owls use their excellent hearing to find prey. Owls have special feathers the make them very quiet fliers. They can attack an animal without being heard, which helps them hunt successfully. Barn owls attack their prey by flying low above the ground (1.5m-4.5 meters above the ground) and grabbing the prey with their feet. They use their bill to nip the prey through the back of the head to kill it, and then they swallow it whole. Barn owls save extra food to eat later, especially during the breeding season. (Marti, 1992)

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

What eats them and how do they avoid being eaten?

Barn owls do not have many predators. Nestlings are sometimes taken by stoats and snakes. Adults may be killed by great horned owls occasionally. Barn owls in western Europe are much smaller than those in North America. These owls are sometimes killed by golden eagles, red kites, goshawks, buzzards, peregrine falcons, lanners, eagle owls and tawny owls.

When facing an intruder, barn owls squint their eyes, spread their wings and sway their head back and forth while hissing. If the intruder is not scared away by this display, the owl falls on its back and strikes at the intruder with its feet. (Marti, 1992)

What roles do they have in the ecosystem?

Barn owls affect the populations of the mammal and bird species that they prey upon. They also provide food for those species that prey upon them. Barn owls are also host to several parasites. (Marti, 1992)

Do they cause problems?

There are no negative impacts of barn owls on humans.

How do they interact with us?

Barn owls limit rodent pest populations, benefiting farmers and others.

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

Are they endangered?

Barn owl populations are decreasing in some areas. In some northern regions, snow is staying on the ground longer. This makes it difficult for barn owl to find food and survive the winter. Barn owls are also poisoned by pesticides that are used to kill weeds or crop pests. Finally, barn owls used to be able to nest successfully on many farms. However, newer farms have fewer buildings for nesting and fewer rodents for food, so they are not very good habitat for barn owls.

Barn owls are protected under the U.S. Migratory Bird Treaty Act and under CITES Appendix II. They are not federally threatened or endangered in the United States, but they are protected in some U.S. states--including Michigan, where they are considered endangered. (Marti, 1992)

Contributors

Kathleen Bachynski (author), University of Michigan-Ann Arbor, Tanya Dewey (editor), Animal Diversity Web.

Kari Kirschbaum (editor), Animal Diversity Web.

Marie S. Harris (author), University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

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

Neotropical

living in the southern part of the New World. In other words, Central and South America.

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.

bog

a wetland area rich in accumulated plant material and with acidic soils surrounding a body of open water. Bogs have a flora dominated by sedges, heaths, and sphagnum.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

cosmopolitan

having a worldwide distribution. Found on all continents (except maybe Antarctica) and in all biogeographic provinces; or in all the major oceans (Atlantic, Indian, and Pacific.

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.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

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

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

oviparous

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

polymorphic

"many forms." A species is polymorphic if its individuals can be divided into two or more easily recognized groups, based on structure, color, or other similar characteristics. The term only applies when the distinct groups can be found in the same area; graded or clinal variation throughout the range of a species (e.g. a north-to-south decrease in size) is not polymorphism. Polymorphic characteristics may be inherited because the differences have a genetic basis, or they may be the result of environmental influences. We do not consider sexual differences (i.e. sexual dimorphism), seasonal changes (e.g. change in fur color), or age-related changes to be polymorphic. Polymorphism in a local population can be an adaptation to prevent density-dependent predation, where predators preferentially prey on the most common morph.

riparian

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

scrub forest

scrub forests develop in areas that experience dry seasons.

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"

suburban

living in residential areas on the outskirts of large cities or towns.

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

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

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
urban

living in cities and large towns, landscapes dominated by human structures and activity.

visual

uses sight to communicate

year-round breeding

breeding takes place throughout the year

References

Perrins, Christopher, M.. et. al., The Encyclopedia of Birds. Facts on File Publications, 1985.

2003. "The Owl Pages" (On-line). Accessed January 26, 2004 at http://www.owlpages.com/species/tyto/alba/Default.htm.

Marti, C. 1992. Barn Owl. Pp. 1-15 in A Poole, P Stettenheim, F Gill, eds. The Birds of North America, Vol. 1. Philadelphia: The Academy of Natural Sciences; Washington DC: The American Ornithologists' Union.

 
University of Michigan Museum of ZoologyNational Science Foundation

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Harris, M. 2002. "Tyto alba" (On-line), Animal Diversity Web. Accessed April 23, 2014 at http://www.biokids.umich.edu/accounts/Tyto_alba/

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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