Giant eagle-owl (Bubo lacteus)

Description

Giant eagle-owl fact file

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

Giant eagle-owl description

As Africa’s largest eagle-owl, the giant eagle-owl is one of the continents most impressive birds of prey. The giant-eagle owl is an imposing bird, with conspicuous ear tufts, and distinctive pink eyelids, on a whitish facial disk rimmed with black ⁽²⁾. The plumage is greyish-brown with light waves of white on the back, lighter, densely barred underparts, and barred flight feathers ^{(2) (4)}. The female is substantially larger than the male, and has a rounder facial disk, while juveniles are distinguished by white patches on the head, and sooty barring over the body ^{(2) (5)}.

Also known as

giant eagle owl, milky eagle owl, Verreaux’s eagle owl.

French

Grand-duc de Verreaux.

Size

Head-body length: 60 – 65 cm ⁽²⁾

Average wingspan: 140 cm ⁽²⁾

Male weight: 1.6 – 1.9 klg ⁽²⁾

Female weight: 2.5 – 3.1 kg ⁽²⁾

Giant eagle-owl biology

The giant eagle-owl is a generalist nocturnal predator, and will consume a large variety of animals. Hedgehogs are the preferred prey of adults, but the giant eagle owl will also prey upon fish, amphibians, reptiles, rodents and other large birds, such as flamingos, herons, raptors and even other eagle-owl species ^{(5) (10)}. This dominating predator hunts from a perch, using its acute eyesight to spot prey, before silently gliding towards the ground and seizing the target in its powerful talons ⁽¹⁰⁾. The giant eagle-owl will also wade into water to catch fish, and demonstrates great agility by catching small birds in the air ^{(10) (11)}.  

The timing of the breeding season varies between localities, but occurs approximately between May and October, peaking between June and September ⁽¹⁰⁾. The giant eagle-owl usually nests in old stick nests constructed by other large bird species, such as the hamerkop (Scopus umbretta) and the secretarybird (Sagittarius serpentarius), but will occasionally nest in tree cavities or tangles of creepers and orchids ^{(9) (10)}. There is much variation in the frequency of breeding, with some pairs breeding yearly, while others breed much more inconsistently ⁽⁹⁾. A pair of eggs are laid, and are incubated solely by the female for some 38 days, but only one chick will survive beyond two weeks, as the adults preferentially feed only one ⁽⁵⁾. The single offspring will leave the nest after around nine weeks, but remains dependant on its parents for the first six months of its life, and can remain with its parents until up to two years of age ⁽⁴⁾. 

Giant eagle-owl range

The giant eagle-owl is a resident of much of southern and central Africa, from sea-level up to an altitude of 3,000 metres. It ranges from northern Ethiopia and Somalia, south to South Africa, with several fragmented populations scattered across West Africa, including Cameroon, Mali and Senegal ^{(2) (7)}. It is believed to have formerly occurred in Lesotho, but is now locally extinct there ⁽⁸⁾.   

Giant eagle-owl habitat

The giant eagle-owl occupies a number of different habitats, including dry savanna, open  woodland, open grassland, agricultural land and riparian habitat such as rivers, marshes and floodplains, but is largely absent from bare desert and dense woodland ^{(2) (9)}. Large trees are required for nesting, and nests are usually found in open woodland, adjacent to floodplains ⁽⁹⁾.

Giant eagle-owl status

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

Giant eagle-owl threats

As the giant eagle-owl is a highly adaptable species, capable of inhabiting a variety of environments, this species is less vulnerable to some typical threats, such as deforestation and land conversion. However, declines have been observed outside of protected areas in South Africa, while the species has been observed as uncommon in much of its West African range ⁽⁹⁾. In addition, the populations in West Africa are highly fragmented, and therefore vulnerable to the effects of chance natural events, such as disease and drought. The ability of populations to recover from a decline is restricted by the species’ slow reproductive rate, and as a result, the giant eagle owl is vulnerable to the effects of direct persecution, such as hunting and trapping ⁽²⁾.

Giant eagle-owl conservation

Observed as common throughout much of its extensive range, the giant eagle-owl is not under immediate threat of extinction ^{(1) (8)}. It is also found in a large number of protected areas throughout its range, while giant eagle-owl populations in riparian habitat are protected in countries that have ratified the Ramsar convention and the African-Eurasian Waterbird Agreement ^{(12) (13)}. However, owing to declines outside of protection areas, and a low reproduction rate, populations should be monitored ^{(2) (9)}.

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

Find out more

For more information on owl conservation projects see:

• The World Owl Trust: 
  http://www.owls.org/

For more information on bird conservation projects in Africa see:

• The African Bird Club: 
  http://www.africanbirdclub.org/

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

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

Authentication

Authenticated (07/05/10) by André Botha, Manager of the Birds of Prey Working Group of the Endangered Wildlife Trust, South Africa.
http://www.ewt.org.za/

Glossary

Amphibians

Cold-blooded vertebrates of the class Amphibia, such as frogs or salamanders, which characteristically hatch as aquatic larvae with gills. The larvae then transform into adults with air-breathing lungs.

Incubate

To keep eggs warm so that development is possible.

Nocturnal

Active at night.

References

1. IUCN Red List (January, 2010):
   http://www.iucnredlist.org/
2. del Hoyo, J., Elliott, A. and Sargatal, J. (1994) Handbook of the Birds of the World. Volume 2: New World Vultures to Guineafowl. Lynx Edicions, Barcelona.
3. CITES (January, 2010):
   http://www.cites.org/
4. The World Owl Trust (January, 2010):
   http://www.owls.org/
5. Wilson, R.T. and Wilson, M.P. (1981) Notes on the giant eagle-owl Bubo lacteus in central Mali. Ardea, 69: 205-208.
6. Integrated Taxonomic Information System (ITIS) (January, 2010)
   http://www.itis.gov/
7. Global Register of Migratory Species (January, 2010)
   http://www.groms.de/
8. Birdlife International (January, 2010)
   http://www.birdlife.org/
9. South Africa Bird Atlas Project 2 (January, 2010)
   http://sabap2.adu.org.za/
10. Biodiversity Explorer: The web of life in South Africa (January, 2010)
    http://www.biodiversityexplorer.org/
11. Kenya Birds (January, 2010)
    http://www.kenyabirds.org.uk/
12. The Ramsar Convention on Wetlands (January, 2010)
    http://www.ramsar.org/
13. The African-Eurasian Waterbird Agreement (January, 2010)
    http://www.unep-aewa.org/