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Bubo bubo
Eurasian eagle-owl


By Jessie Cantrell

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Aves
Order: Strigiformes
Family: Strigidae
Genus: Bubo
Species: Bubo bubo
Members of this Species

Geographic Range

Eagle owls primarily live in the Palearctic region, although they can travel as far south as the Oriental Region and Ethiopian Region and as far north as the far reaches of Siberia. They are found in North Africa, Europe, The Middle East, and Asia. ("The Eurasian Eagle Owl", 2002; Konig, et al., 1999; Parry-Jones, 1998; "Eurasian Eagle Owl", 2003)

Biogeographic Regions
palearctic ; oriental ; ethiopian

Other Geographic Terms
holarctic ; cosmopolitan

Habitat

These owls can be found in many different kinds of habitats including wooded areas (coniferous forests), warm deserts, mountain ranges, and riverbeds. They prefer to live in rocky landscapes, especially when nesting. Eagle owls search for habitats with adequate food supply and proper nesting sites. Their habitats vary greatly, and they can also be found in open areas that have few trees like farmlands and grasslands. (; "Eurasian Eagle Owl", 2003; "The Eurasian Eagle Owl", 2002)

Habitat Regions
temperate ; polar ; terrestrial

Terrestrial Biomes
tundra ; taiga ; desert or dune ; savanna or grassland ; forest ; scrub forest ; mountains

Wetlands
marsh ; swamp

Other Habitat Features
suburban ; agricultural

Physical Description

Range mass
1600 to 4200 g
(56.39 to 148.02 oz)

Average mass
2800 g
(98.68 oz)

Range length
58 to 71 cm
(22.83 to 27.95 in)

Average length
65 cm
(25.59 in)

Range wingspan
1.5 to 2 m
(4.92 to 6.56 ft)

Eagle owls are the largest owls in the world, and they are best known for their large, striking, orange eyes. They are often called the Old World version of America's widely distributed great horned owl. They have prominent ear tufts and are primarily brown-black and tawny-buff in color. Their facial disk is heavily marked with black, gray, and white. Their upper parts are darker than their lower parts, which have black streaks, and their throat is white. It is interesting to note that these owls become paler in the northeastern geographic regions and get progressively darker as you move to the Pacific coast. Also, size tends to decrease from north to south, and east to west. ("The Eurasian Eagle Owl", 2002; Konig, et al., 1999; "Eurasian Eagle Owl", 2003; )

Other Physical Features
endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism
female larger

Reproduction

Both sexes are usually solitary but they pair up during courtship. They advertise potential breeding sites by digging a shallow depression into the earth and emitting a light staccato note and various clucking sounds. They also use these calls to keep track of their mate's location. People often hear them calling to each other. They keep the same partners for life. Eagle owls are very sensitive to their environment. If there is not enough food resources, will mate at a much slower rate and later into the year. When they have sufficient habitats and plentiful food, their mating rate increases significantly. ("The Eurasian Eagle Owl", 2002; Konig, et al., 1999; Parry-Jones, 1998; Penteriani, et al., 2002; "Eurasian Eagle Owl", 2003; )

Mating System
monogamous

Breeding interval
Breeding occurs once a year.

Breeding season
The breeding season lasts from December to April.

Range eggs per season
1 to 4

Average eggs per season
3

Range time to hatching
2 to 3 months

Range time to fledging
20 to 24 weeks

Range time to independence
9 to 12 months

Range age at sexual or reproductive maturity (female)
1 to 3 years

Range age at sexual or reproductive maturity (male)
1 to 3 years

Eagle owls form pairs in early fall and nest in late January and early February. They prefer to nest in crevices between rocks, sheltered cliff ledges, cave entrances, as well as abandoned nests of other large birds. Usually egg laying begins in late winter. They usually have one batch of eggs per year ranging from one to four white eggs. This number depends on the food availiable in their area. When the owlets hatch, they are brooded for about two weeks. In about three weeks the young begin to feed and swallow by themselves. By week five they can walk around the nesting area and begin to fly about 60 days, although for only a few meters. They leave the nest or are driven out in the fall (Sept-Nov.) Eagle owls are able to breed from the ages of 2-31 years. ("The Eurasian Eagle Owl", 2002; "Eurasian Eagle Owl", 2003; )

Key Reproductive Features
seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization

Once the eggs are laid, they are incubated by the female alone. The male kills prey and feeds his mate. Once the eggs hatch, the male continues to bring food to the female for the next two weeks. During this time the female stays at the nest protecting her young from predators and teaching them how to eat on their own. All owls are imprinted by their mothers, which means they will imitate the first animal they see. This makes it difficult to release owls into captivity if they are not raised by an owl parent. If an owl sees a human when they are born, they think they are human too. ("Eurasian Eagle Owl", 2003; "The Eurasian Eagle Owl", 2002; Parry-Jones, 1998)

Parental Investment
male parental care ; female parental care

Lifespan/Longevity

Range lifespan
Status: wild

68 (high) years

Range lifespan
Status: captivity

64 (high) years

Typical lifespan
Status: wild

10 to 20 years

Typical lifespan
Status: captivity

20 to 60 years

Eagle owls have relatively long life spans once they reach adulthood. They have no real natural enemies. In the wild, they live for approximately 20 years, but they can live more than 60 years in captivity. ("The Eurasian Eagle Owl", 2002; Parry-Jones, 1998)

Behavior

Range territory size
15 to 80 km^2

Average territory size
42.5 km^2

Eagle owls are primarily solitary animals except during the mating period. They fiercely defend their territory against other owls and will only overlap territories slightly if food is sparce. Eagle owls prefer to stay within the same territory unless they are forced to leave due to food shortages or if they are driven out by other owls. Despite their large size, they are very elusive creatures, which makes them difficult to study in their natural habitats. Eagle owls spend most of their days roosting high in trees remaining relatively inactive. They are nocturnal and become active at dusk and remain so throughout the night. When food is rare, they will hunt during the day. ("The Eurasian Eagle Owl", 2002; )

Key Behaviors
arboreal ; flies; nocturnal ; crepuscular ; solitary ; territorial

Communication and Perception

Eagle owls are known for their loud calls. They are heard far more than they are seen. They use their various hoots and clucks to let others know they have entered or are entering certain territories. Different hoots represent different moods and are easily recognizable between each member of the species. Also, eagle owls are able to decipher the size and distance of intruders based on the intensity of their call. They also use a low gutteral hoot to attract mates. It's interesting to note that even though eagle owls are difficult to study, they (like other owls) cough up what is known as an owl pellet after their stomach goes through the digestive process. These owl pellets contain the hair, feathers, and bones of prey they were unable to digest. These pellets are very useful to scientists because they help them understand the food habits of these elusive birds. ("The Eurasian Eagle Owl", 2002; Parry-Jones, 1998)

Communication Channels
visual ; acoustic

Perception Channels
vibrations

Food Habits

Eagle owls are carnivores. They are primarily nocturnal hunters and have various hunting techniques. They take their prey in flight or on the ground. They prefer to hunt in open spacious locations rather than forests. Most owls are very capable hunters and the eagle owl is no exception. Owl wings have evolved to make very little noise when flapping. With their night vision, advanced hearing, and silent flight they are the hit men of their territory. Their prey usually has no idea they were being stalked. They feed on almost anything they can catch including rats, mice, voles, beetles and even large prey like deer fawns and foxes. They will also feed on other birds such as crows, ducks, and even other owls. Dominant prey can vary from habitat to habitat but is most often small rodents. ("The Eurasian Eagle Owl", 2002; Parry-Jones, 1998)

Animal Foods
birds; mammals; reptiles; insects

Predation

Once eagle owls reach adulthood, they are at a very low risk of predation. They are at the top of the food chain in their niche. They are not a major food source for any other species. The only time they are at risk of predation is during their early years. They are at risk from any predator too large for them too eat. Fortunately, the mother stays with the young for most of this period and keeps the predators at bay. Due to their striped, spotted, and varied coloring, they are extremely well camouflaged, especially when perching in the trees. (Parry-Jones, 1998)

Anti-predator Adaptations
cryptic

Ecosystem Roles

Eagle owls are at the top of their food chain. They are particularly useful in keeping the number of rodents down in their various ecosystems. The removal of this species can cause the rodent population in a given area to grow significantly. Therefore, they may be a keystone predator. (Konig, et al., 1999; Parry-Jones, 1998; )

Ecosystem Impact
keystone species

Economic Importance for Humans: Positive

Eagle owls are economically beneficial to farmers that want to keep the number of rodents down on their land. Many birdwatchers will also pay to get a glimpse of this rare bird in its natural habitat as well as in zoos. ("The Eurasian Eagle Owl", 2002; "Eurasian Eagle Owl", 2003)

Positive Impacts
ecotourism ; research and education; controls pest population

Economic Importance for Humans: Negative

There are no known adverse affects of the eagle owl on humans.

Conservation Status

IUCN Red List [Link]
Least Concern

US Migratory Bird Act [Link]
No special status

US Federal List [Link]
No special status

CITES [Link]
Appendix II; Appendix III

Eagle owls are considered rare but not yet threatened. Their numbers are steadily declining due to habitat loss from human encroachment. ("Eurasian Eagle Owl", 2003)

For More Information

Find Bubo bubo information at

Contributors

Matthew Wund (editor), University of Michigan.

Jessie Cantrell (author), University of Michigan, Phil Myers (editor), Museum of Zoology, University of Michigan.

References

The Peregrine Fund. 2003. "Eurasian Eagle Owl" (On-line). The Peregrine Fund. Accessed March 21, 2003 at http://www.peregrinefund.org/Explore_Raptors/owls/eagleowl.html.

Centre for the Conservation of Specialized Species. 2002. "The Eurasian Eagle Owl" (On-line ). The Centre for the Conservation of Specialized Species. Accessed 3/21/03 at http://www.conservationcentre.org/scase21.html.

Konig, C., J. Becking, F. Weick. 1999. Owls: A Guide to the Owls of the World. New York, NY: Yale University Press.

Parry-Jones, J. 1998. Understanding Owls: Biology, Management, Breeding, Training. New York, NY: David and Charles.

Penteriani, V., M. Gallardo, P. Roche. 2002. Landscape structure and food supply affect eagle owl (Bubo bubo) density and breeding performance: a case of intra-population heterogeneity. Journal of Zoology, 257: 365-372.

Woburn Safari Park, "Woburn Safari Park" (On-line ). Amazing Animal Facts. Accessed 3/21/03 at http://www.woburnsafari.co.uk/animalfacts.asp?aID=11.

To cite this page: Cantrell, J. 2004. "Bubo bubo" (On-line), Animal Diversity Web. Accessed February 12, 2012 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Bubo_bubo.html

Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

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