Marsh owl (Asio capensis)

Also known as: African marsh owl
  
French: Hibou des marais africain
KingdomAnimalia
PhylumChordata
ClassAves
OrderStrigiformes
FamilyStrigidae
GenusAsio (1)
SizeHead-body length: 29 – 36 cm (2)
Wingspan: 82 – 99 cm (2)
Weight225 – 375 g (2)

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

Distinctive of many African wetlands and savannas, the marsh owl is a medium-sized owl, with a round head and small inconspicuous ear tufts. The tail barring and wing feathers are buffish in colour, while the underside of the body may be darkly barred (2). The eyes are surrounded by conspicuous dark rings and the greyish bill has a black tip. Marsh owls exhibit sexual dimorphism and the sexes are distinguished by the females’ larger size and longer tail (4). Juveniles have a dark facial disk that is outlined in black (2).

Three subspecies of marsh owl are recognised: Asio capensis tingitanus is distinguished from the nominate subspecies A. c. capensis by white spotting and rufous colouration on the underparts, while A. c. hova is distinguished by larger distinct barring across the body (2).

The marsh owl has an extensive range throughout much of southern and Central Africa, extending from South Africa to Ethiopia and Madagascar, with scattered populations in West Africa including Cameroon, Chad, Morocco and Senegal (2). The marsh owl is non-migratory, but seasonal movements may occur in response to fluctuations in rainfall, and vagrants have been recorded as far north as Portugal, Spain and the Canary Islands (2) (3) (5) (6).  A. c. tingitanus is endemic to northwest Morocco, A. c. capensis occurs in scattered populations across West Africa from Senegal, to Chad and Cameroon, and from Sudan and Ethiopia south towards the Cape of South Africa, avoiding the most arid areas, while A. c. hova is endemic to the island of Madagascar (2). The marsh owl formerly occurred in Algeria, but is now believed to be locally extinct there (3). Found up to 1,500 metres above sea level, the marsh owl is reportedly most abundant between 1,300 and 2,000 metres in Kenya (7) (8).

The species’ name may suggest that it is restricted to marshes, but the marsh owl can be found within a multitude of habitats, ranging from estuarine marshes and mangroves, to sub-tropical grasslands, open savannas, inland wetlands and agricultural areas (7). It is likely that seasonal fluctuations in rainfall and water availability influence habitat selection throughout the marsh owl’s range (2).

An efficient hunter, the marsh owl soars silently in the air with steady wingbeats and short glides. As a generalist feeder, the marsh owl consumes a large variety of prey including small mammals, such as rodents and mustelids, birds, amphibians, reptiles and large insects (2). Active at night and during the day, the marsh owl uses its acute eyesight to spot prey, which is caught in large talons, before being taken to a hidden location and eaten (9).

The breeding season peaks in March in North Africa and between December and April in Southwest Africa, with shallow nests constructed on the ground in a tuft of dense tall grass. A brood of two to three eggs is incubated by the female for approximately 28 days, with offspring fledging around 35 days after hatching (2).

As the marsh owl is found in a number of habitats, threats vary between localities. In Morocco there are a reportedly low number of breeding pairs due to habitat degradation, and the species may also occur at low densitites in Madagascar. Throughout the species’ range, marsh owl foraging and nesting habitat may be altered through overgrazing by livestock, drainage of wetlands, grassland fires and habitat degradation from human encroachment (2).

Listed as Least Concern on the IUCN Red List of Threatened Species, the marsh owl is believed to be common throughout much of its extensive range, with no evidence of a decline (1) (7).   The marsh owl is also present in a large number of protected areas, and is reportedly common in Kruger National Park in South Africa (2) (9). Furthermore, wetland habitats used by the marsh owl are also protected in countries that have ratified the Ramsar convention and the African-Eurasian Waterbird Agreement (10) (11).

For more information on bird conservation projects in Africa, see:

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

Authenticated (15/03/10) by André Botha, Manager of the Birds of Prey Working Group of the Endangered Wildlife Trust, South Africa. 
http://www.ewt.org.za/home.aspx

  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 - New World Vultures To Guineafowl. Vol. 2. Lynx Edicions, Barcelona.
  3. CITES (January, 2010)
    http://www.cites.org
  4. Ansara-Ross, T.M., Wepener, V., Verdoorn, G.H. and Ross, M.J. (2008) Sexual dimorphism of four owl species in South Africa. Ostrich, 79: 83-86.
  5. Global Register of Migratory Species (January, 2010)
    http://www.groms.de/
  6. Smalley, M.E. (1983) The marsh owl Asio capensis: A wet season migrant to the Gambia. Malimbus, 5: 31-33. Available at:
    http://malimbus.free.fr/articles/V5/05031033.pdf
  7. BirdLife International (January, 2010)
    http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=2323&m=1
  8. Kenya Birds (January, 2010)
    http://www.kenyabirds.org.uk/
  9. Biodiversity Explorer: The web of life in South Africa (January, 2010)
    http://www.biodiversityexplorer.org/
  10. The Ramsar Convention on Wetlands (January, 2010)
    http://www.ramsar.org/
  11. The African-Eurasian Waterbird Agreement (January, 2010)
    http://www.unep-aewa.org/