Cape Eagle-Owl (Bubo capensis)

Cover image: Cape Eagle-Owl by Jorrie Jordaan – Rhodes Quarry, Grahamstown, Eastern Cape – BirdPix No. 86047

Identification

The Cape Eagle-Owl is a large, heavily marked eagle-owl with conspicuous ‘eartufts’ and an overall brown and rufous-buff appearance.

Adults have dark brown upper parts with tawny blotches, particularly on the hind neck. The under parts, from the upper breast to the flanks, are heavily blotched with dark brown on a pale background. This blotching is larger and more concentrated on the breast and has been likened to a ‘breast plate’. The belly is whiteish with bold, dark brown barring. The throat is white and conspicuous when calling.

The tail is dark brown with broad tawny-coloured barring. The Cape Eagle Owl has large, powerful feet which are off-white and fully feathered on the upper sides. The eyes are deep orange (not yellow) and the bill and cere are black. Sexes are alike in plumage coloration. Juveniles resemble the adults but are paler and their ear tufts are either absent or reduced.

The Cape Eagle-Owl can easily be mistaken for the slightly smaller Spotted Eagle-Owl (Bubo africanus), particularly the rare rufous morph of that species which has orange-yellow eyes. The typical colour-form of the Spotted Eagle-Owl is generally greyer and less heavily marked, especially on the breast. They also have yellow (not orange) eyes and less powerful feet.

Status and Distribution

The Cape Eagle Owl is an uncommon to rare resident. It is easily overlooked and is likely to be more numerous than records suggest, notably in Namibia and the Northern Cape.

It has a highly fragmented distribution, occurring from the Ethiopian highlands, to Kenya, Uganda and Tanzania. It is more widespread in southern Africa from Zimbabwe and extreme western Mozambique to South Africa, Lesotho and Namibia. It marginally reaches into southern Angola and possibly also western Eswatini (Swaziland). The Cape Eagle-Owl has not yet been recorded from Botswana.

The Cape-Eagle-Owl is not considered threatened and populations may have increased in some areas due to birds moving into quarries and even cities to roost on buildings. Southern African populations are unlikely to be facing any immediate threats. The Cape Eagle-Owl is potentially impacted by fires, overgrazing, afforestation, and they are occasionally killed on roads at night.

Habitat

The Cape Eagle-Owl occurs in a range of biomes from Desert, Succulent Karoo, Nama Karoo and Fynbos to Grassland and Savanna. Despite this, the Cape Eagle-Owl is very habitat specific, favouring rocky outcrops, cliffs and gorges in a variety of surrounding habitats. The Cape Eagle-Owl sometimes roosts and hunts in towns and cities adjacent to its preferred rocky habitat.

It occurs from sea level in the Western Cape to above 3 000 m in the Drakensberg. The Cape Eagle-Owl is most numerous in the Alpine grasslands of Lesotho and the Drakensberg of KwaZulu-Natal and the Eastern Cape.

Behaviour

The Cape Eagle-Owl is usually solitary but may roost in pairs or with dependant fledglings. Roosts by day in a cave or on a ledge, but also in the shade of a rock or bush. They usually roost on the ground, and less often in trees. When roosting, they are very reluctant to fly, flushing only at the last moment. Once flushed they will often perch in the open, where where they may be mobbed by raptors and ravens. The Cape Eagle-Owl typically flies to a prominent perch at dusk, but they occasionally emerge at sunset and may also sunbathe in the early morning sunshine. Roost and nest sites can be recognised by thick accumulations of white droppings, large pellets and prey remains.

The Cape Eagle-Owl hunts from a perch, swooping swiftly and silently onto prey, which is captured with the powerful feet. Smaller prey is swallowed whole while larger prey is torn into pieces with the bill. Cape Eagle-Owls feed mostly on small to medium-sized mammals, but the diet includes a wide range of other vertebrate and invertebrate species.

Mammals taken range in size from Cane Rats and young Rock Hyrax down to small rodents and shrews. Red Rock Hares (Pronolagus spp.) form an important part of the diet in some areas. Other mammals recorded in the diet include Springhares, Genets, Mongooses, Sengis (Elephant Shrews) and the lambs of Klipspringer (Oreotragus oreotragus) and Common Duiker (Sylvicapra grimmea). The Cape Eagle-Owl also feeds on bats which they catch in flight as the bats leave their roosts.

Typical bird prey includes Doves, Pigeons, Helmeted Guineafowl, Francolins, Starlings, Robin-Chats etc. The Cape Eagle-Owl is also known to eat other Owls, Hamerkop, Lanner Falcon and Rock Kestrel, amongst others. Domestic chickens are taken on rare occasions. Small lizards, and invertebrates, are readily consumed, including crabs, scorpions, solifuges, spiders, beetles and grasshoppers.

Courtship displays involve much hooting and take place at dusk prior to breeding. The pair sit facing each other, the female sitting upright as the male bows at her with each hoot. Their white throats become conspicuous as they are puffed out while calling.

The Cape Eagle-Owl is monogamous and is a territorial, solitary nester. The nest is a simple, unlined scrape on bare ground beneath a boulder, on a rock ledge or in a cave. Nests are often well screened by vegetation and are regularly situated near a drainage line. The nest site is used repeatedly, but not necessarily every year. The breeding season in Southern Africa varies depending on the region. In Zimbabwe and north-eastern South Africa breeding takes place from May to July and from June to September in the south-western Cape.

One to three (usually two) white eggs are laid per clutch and eggs are laid two to four days apart. Incubation starts once the first egg has been laid. Incubation lasts up to 38 days and is performed mainly by the female. The male feeds the female at or near nest and he may take over incubation while the female feeds. Young chicks are brooded and fed by the female on food brought in by the male. As the nestlings get older, the female assists the male in supplying food. Fledglings are dependent on their parents for at least the first 2 or 3 months after fledging.

Older chicks leave the nest for surrounding cover at around 45 days old, but can only fly after 75 days or so. Cape Eagle-Owls are probably single-brooded, breeding on average every second year.

Further Resources

This species text is adapted from the first Southern African Bird Atlas Project (SABAP1), 1997.

The use of photographs by Alan Collett, Craig Peter, Jorrie Jordaan, Kevin Lavery, Liezl De Klerk, Maans Booysen and Pamela Kleiman is acknowledged.

Virtual Museum (BirdPix > Search VM > By Scientific or Common Name).

Other common names: Kaapse ooruil (Afrikaans); isiKhovampondo (Zulu); Khuhunu, Phikuphiku (Tswana); Kaapse Oehoe (Dutch); Grand-duc du Cap (French); Kapuhu (German); Bufo do Cabo (Portuguese).

List of species available in this format.

Recommended citation format: Tippett RM 2024. Cape Eagle-Owl Bubo capensis. Biodiversity and Development Institute. Available online at https://thebdi.org/2024/04/27/cape-eagle-owl-bubo-capensis/

Bird identification, birding