Eurasian eagle-owl (Bubo bubo)

Description

Eurasian eagle-owl fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Eurasian eagle-owl description

Considered to be one of the largest owls in the world, the Eurasian eagle-owl is an impressive and majestic bird, with distinctive, prominent ear-tufts, a barrel-shaped body, and vivid orange eyes. The plumage is buffy-brown, paler on the underparts, and heavily mottled and streaked with black, with fine barring on the belly and flanks, and dark bars on the wings and tail. The throat is white ^{(2) (4) (5) (6)} and is used in intraspecific communication, as a visual signal associated with vocal displays ^{(7) (8) (9)}. The ‘facial disc’, the flat or concave arrangement of feathers on the face, typical of owls, is greyish ^{(2) (5)}, and is less developed than in many other owl species ⁽⁶⁾. The beak is black, and the legs and large, powerful toes are fully feathered buffy-white ⁽²⁾.

The Eurasian eagle-owl is quite variable in appearance across its range, with a number of subspecies recognised, which differ in size, colouration, and the strength of the dark markings ^{(2) (5) (6) (10) (11)}. The juvenile Eurasian eagle-owl can be recognised by its rudimentary ear-tufts, narrowly barred underparts, and buffy down on the head ⁽²⁾. The distinctive call of this species is a deep, booming ooo-hu ^{(2) (4) (5)}, while other vocalisations include a quiet, guttural chuckling, and the bark-like scream of the female ^{(2) (4) (12)}.

Also known as

common eagle-owl, Eurasian eagle owl, great eagle-owl, northern eagle-owl.

Size

Length: 60 - 75 cm ⁽²⁾

Wingspan: 160 - 188 cm ⁽²⁾

Male weight: 1.5 - 2.8 kg ⁽²⁾

Female weight: 1.75 - 4.2 kg ⁽²⁾

Eurasian eagle-owl biology

Usually most active at dawn and dusk ^{(2) (4)}, the Eurasian eagle-owl has a powerful, fast flight, which is somewhat reminiscent of that of a buzzard (Buteo buteo) ^{(2) (4) (16)}. Hunting occurs from an open perch or in flight, and the owl may also search rock crevices for roosting birds, take both adult and young birds from nests, or even plunge into water to capture fish ^{(2) (16)}. The diet mainly consists of mammals, up to the size of adult hares or even young deer, as well as birds up to the size of herons and buzzards, and occasionally amphibians, reptiles, fish and insects ^{(2) (5) (6) (16)}.

The Eurasian eagle-owl usually begins breeding from late winter ^{(2) (5)}. The nest is located on a sheltered cliff ledge, in a cave or crevice, in the old nest of another species (such as storks or large birds of prey), or occasionally in a tree hole or on the ground ^{(2) (4) (5) (16)}. The species has always been considered to be monogamous, but some cases of bigamy have been recorded recently ⁽¹⁵⁾. A breeding pair may use the same nest site over several years ⁽²⁾. Between one and five eggs are laid, and are incubated by the female for 34 to 36 days, during which time the male brings food to the nest. The young owls first leave the nest at around five weeks, but cannot fly until about seven weeks old, and remain dependent on the adults for a further three to four months ^{(2) (5) (16)}, not generally starting to disperse until approximately 170 days old ⁽¹⁷⁾ The Eurasian eagle-owl reaches sexually maturity at 1 year ⁽¹⁵⁾, and may live up to 21 years or more in the wild, or to an impressive 60 years in captivity ⁽²⁾.

Eurasian eagle-owl range

The Eurasian eagle-owl has one of the largest ranges of any eagle-owl ⁽⁶⁾, being found across much of Europe, through the Middle East, Russia and Asia, and as far east as China, Korea and Japan ^{(2) (5) (11) (13)}. Although generally absent from Britain and Ireland ⁽¹¹⁾, small numbers are now beginning to breed in Britain ⁽¹⁴⁾.

Eurasian eagle-owl habitat

This owl usually inhabits natural rocky areas with cliffs and ravines, as well as quarries and buildings, patches of woodland or scattered trees. It also occurs in open forest, taiga, wooded steppe, semi-desert, and farmland with suitable rocky areas ^{(2) (4) (5) (11)}, and can be found at elevations of up to about 2,000 metres in Europe and 4,500 metres in Central Asia and the Himalayas ^{(2) (11)}. Recently, this species has started to colonise urban habitats and is now breeding in several towns in Europe ⁽¹⁵⁾.

Eurasian eagle-owl status

Classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾ and listed on Appendix II of CITES ⁽³⁾.

Eurasian eagle-owl threats

The Eurasian eagle-owl underwent a significant decline in Europe during the 20^th century, due mainly to human persecution ^{(2) (13) (16)}. Pesticide use and poisoning from mercury seed-dressings have also been a problem, as have collisions with vehicles, barbed wire ⁽²⁾ and powerlines ^{(18) (19) (20)}. In addition, diseases such as myxomatosis and rabbit haemorrhagic disease have decimated rabbit populations in some areas, with severe knock-on effects for the Eurasian eagle-owl ^{(2) (21)}. Although the species has now recovered to some extent, and is not currently considered globally threatened, illegal persecution still occurs, and the population remains below its former levels ^{(2) (5) (13)}. The Eurasian eagle-owl is thought to be highly sensitive to disturbance, particularly during incubation, which may cause adults to abandon eggs and even small young ^{(2) (22)}.

Eurasian eagle-owl conservation

The Eurasian eagle-owl has recovered to some extent in Europe as a result of improved protection, extensive reintroduction / restocking programmes, and an increased food supply due to clear-felling and the proliferation of refuse tips, with the resulting increases in rats and other rodents ^{(2) (5) (16)}. Within Europe, the species is protected under the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) ⁽²³⁾ and the EC Birds Directive ⁽²⁴⁾, and international trade in the species should be controlled under its listing on the Convention on International Trade in Endangered Species (CITES) ⁽³⁾. Little detailed data is available on Asian populations ⁽²⁾. Conservation measures recommended for the Eurasian eagle-owl include protecting its habitat from development and extensive logging, as well as action to prevent collisions with powerlines ^{(19) (20)}. Breeding pairs in Britain are thought to represent escapes from captivity, and it has been recommended that the potential impact of this large bird of prey on native wildlife be assessed ⁽¹⁴⁾.

View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more

For more information on the Eurasian eagle-owl, see:

• BBC Wildlife Finder:
  http://www.bbc.co.uk/nature/species/Eurasian_Eagle-owl

To find out more about the conservation of this and other owl species see:

• World Owl Trust:
  http://www.owls.org/
• The Peregrine Fund:
  http://www.peregrinefund.org/
• RSPB - Eagle Owls in Britain:
  http://www.rspb.org.uk/ourwork/policy/species/nonnative/eagleowls.asp

For more information on this and other bird species please see:

• BirdLife International:
  http://www.birdlife.org

Authentication

Authenticated (18/08/10) by Dr Vincenzo Penteriani, Estación Biológica de Doñana, C.S.I.C., Department of Conservation Biology, c/ Americo Vespucio s/n, 41092 Seville, Spain.
http://www.vincenzopenteriani.org/

Glossary

Incubate

To keep eggs warm so that development is possible.

Intraspecific

Arising or occurring within a species.

Monogamous

Having only one mate during a breeding season, or throughout the breeding life of a pair.

Steppe

A biome (or subdivision of the Earth’s surface) that is composed of a swathe of temperate grassland stretching from Romania to China.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

Taiga

The sub-arctic forest of the high northern latitudes that surrounds the pole and is mainly composed of coniferous trees.

References

1. IUCN Red List (October, 2009)
   http://www.iucnredlist.org/
2. del Hoyo, J., Elliott, A. and Sargatal, J. (1999) Handbook of the Birds of the World. Volume 5: Barn-Owls to Hummingbirds. Lynx Edicions, Barcelona.
3. CITES (October, 2009)
   http://www.cites.org/
4. Peterson, R.T., Mountfort, G. and Hollom, P.A.D. (1993) Collins Field Guide: Birds of Britain and Europe. HarperCollins Publishers, London.
5. World Owl Trust (October, 2009)
   http://www.owls.org/
6. Warhol, T. (2007) Owls. Marshall Cavendish Benchmark, New York.
7. Penteriani, V., Delgado, M.M., Alonso-Alvarez, C. and Sergio, F. (2007) The importance of visual cues for nocturnal species: eagle owls signal by badge brightness. Behavioral Ecology, 18: 143-147.
8. Penteriani, V., and Delgado, M.M. (2009) The dusk chorus from an owl perspective: eagle owls vocalize when their white throat badge contrasts most. PLoS ONE, 4(4): e4960.
9. Penteriani, V., Delgado, M.M., Campioni, L. and Lourenço, R. (2010) Moonlight makes owls more chatty. PLoS ONE, 5(1): e8696.
10. Integrated Taxonomic Information System (ITIS) (October, 2009)
    http://www.itis.gov/
11. Weick, F. (2006) Owls: Strigiformes. Annotated and Illustrated Checklist. Springer, Berlin.
12. Delgado, M.M. and Penteriani, V. (2007) Vocal behaviour and neighbour spatial arrangement during vocal displays in eagle owls (Bubo bubo). Journal of Zoology, 271: 3-10.
13. BirdLife International (October, 2009)
    http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=2215&m=0
14. RSPB (October, 2009)
    http://www.rspb.org.uk/
15. Penteriani, V. (August, 2010) Pers. comm.
16. The Peregrine Fund: Eurasian Eagle-Owl (Bubo bubo) (October, 2009)
    http://www.peregrinefund.org/explore_raptors/owls/eagleowl.html
17. Delgado, M.M., Penteriani, V., Revilla, E. and Nams, V.O. (2010) The effect of phenotypic traits and external cues on natal dispersal movements. Journal of Animal Ecology, 79: 620-632.
18. Martínez, J.A., Martínez, J.E., Mañosa, S., Zuberogoitia, I. and Calvo, J.F. (2006) How to manage human-induced mortality in the Eagle Owl Bubo bubo. Bird Conservation International, 16: 265-278.
19. Rubolini, D., Bassi, E., Bogliani, G., Galeotti, P. and Garavaglia, R. (2001) Eagle owl Bubo bubo and power line interactions in the Italian Alps. Bird Conservation International, 11: 319-324.
20. Sergio, F., Marchesi, L., Pedrini, P., Ferrer, M. and Penteriani, V. (2004) Electrocution alters the distribution and density of a top predator, the eagle owl Bubo bubo. Journal of Applied Ecology, 41: 836-845.
21. Martínez, J.A. and Zuberogoitia, I. (2001) The response of the eagle owl (Bubo bubo) to an outbreak of the rabbit haemorrhagic disease. Journal of Ornithology, 142: 204-211.
22. Penteriani, V., Delgado, M.M., Maggio, C., Aradis, A. and Sergio, F. (2005) Development of chicks and predispersal behaviour of young in the eagle owl Bubo bubo. Ibis, 147: 155-168.
23. Council of Europe: Bern Convention (October, 2009)
    http://conventions.coe.int/Treaty/EN/Treaties/Html/104.htm
24. EC Birds Directive (October, 2009)
    http://www.jncc.gov.uk/page-1373