African Fish Eagle (Haliaeetus vocifer)

Cover image: African Fish Eagle by Malcolm Robinson – Albert Falls Nature Reserve, KwaZulu-Natal – BirdPix No. 140988

Identification

The African Fish Eagle with its distinctive plumage and characteristic call, is one of Africa’s most iconic bird species. It is a large and robust eagle. Females are 10-15% larger than males and can attain 3.6 kg and a wingspan up to 1.91 m. Males are weigh up to 2.5 kg.

Adult African Fish Eagles are unmistakeable. The all-white head, breast and tail contrast with the black and chestnut wings, back and underparts. The sexes are very similar in terms of plumage but females have more extensive white on the breast.

Juvenile and immature birds have patchy brown and white plumage and are often scruffy looking. They attain full adult plumage at 4 to 5 years of age and the transition into adult plumage varies individually. Each successive moult leads to a gradual ‘neatening’ of the plumage. White areas become cleaner, and dark areas more uniform. In young birds the crown is largely brown, with a blackish eyebrow. The face, neck, mantle and upper rump are whitish, sometimes with dark streaking. The breast is heavily streaked dark brown, and the belly is mostly blackish. The remainder of the upper parts are mottled in brown and white. The tail is white with a dark tip becoming shorter as the bird nears adult plumage. The cere and bare facial skin is pinkish and the legs are pale greyish-yellow.

In flight, adult African Fish Eagles are seen to have broad wings with black flight feathers and chestnut underwing coverts that contrast strongly with the white head and tail. Juveniles and immatures have mostly white underwing coverts and dark flight feathers with large white windows on the primaries. They also have an off-white tail with a broad, dark terminal band.

Adults are distinctive and are not easily mistaken for any other species. They most resemble the Palm-nut Vulture (Gypohierax angolensis) but that species is slightly smaller, with white (not chestnut) underparts. Palm-nut Vultures also have more rounded wings and a black tail with a white tip. The bare facial skin is pink as opposed to the yellow of the African Fish Eagle.

Juvenile and immature African Fish Eagles are more problematic to identify and perhaps most resemble the Western Osprey (Pandion haliaetus). The Western Osprey is much smaller, with a pale crown, blackish eye stripe and mask, and yellow eyes. In flight the Western Osprey shows narrower wings with a distinctive bend at the carpal joint. The inner underwing coverts are mostly white (not brown) with a dark brown central bar that extends from the wing base to the wrist. The flight feathers are faintly barred and the tail is considerably longer.

Status and Distribution

The African Fish Eagle is a locally common resident. It is an Afrotropical species and occurrs throughout most of sub-Saharan Africa.

In southern Africa it is fairly widespread in the higher rainfall eastern and southern parts. However, its occurrence is patchy owing to the nature of its habitat. It is sparsely distributed in the arid to semi-arid central and western parts where it is mainly associated with larger dams, but occurs along the entire length of the Orange River.

The African Fish Eagle is most numerous in the Okavango Delta and along the Chobe and Zambezi Rivers. It is also common in the lowveld and along the east coast littoral from Maputo in Mozambique to the Olifants River in the Western Cape. The African Fish Eagle is surprisingly scarce along much of southern Mozambique coast.

Overall, the current range is thought to reflect the historical distribution. The African Fish Eagle is not threatened globally, but is Vulnerable in Namibia due to its small population. In South Africa, some populations have been negatively impacted by disturbance, development and wetland degradation. However, artificial impoundments have provided much additional habitat. There is no evidence of a decreases in numbers despite high pesticide levels in at least some eggs.

Habitat

The African Fish Eagle is associated with aquatic habitats across all biomes of southern Africa. The African Fish Eagle favours estuaries, coastal and inland lakes, larger rivers and pans, floodplains and artificial impoundments. Sometimes also hunts in marine habitats along the coastline. The African Fish Eagle can occasionally be found far from water where they prey on birds or feed on carcasses.

It avoids high mountainous regions, including Lesotho and much of the Drakensberg.

Behaviour

African Fish Eagles are generally encountered solitarily or in pairs, but can occur at high densities under suitable conditions where occasional flocks of up to 75 birds have been recorded.

The African Fish Eagle spends the majority of its time perched in trees overlooking the water, either scanning for prey or watching out for territorial neighbours. The African Fish Eagle soars well and pairs frequently soar together, often while calling. They are most vocal at dawn.

Roosts near water, in tall trees or on cliffs.

Pairs spend most of the day within sight of each other. African Fish Eagles are strongly territorial year-round and pairs don’t hesitate to defend their territories from conspecifics. The larger females are more aggressive than the males. Rival birds that wander into the territory are either chased off or attacked. Fighting birds sometimes engage in cartwheeling flight, where two birds (often females), catch each other by feet and cartwheel down, sometimes plummeting more than 100 m. They usually separate just before hitting the ground or water, but sometimes crash-land into vegetation while still interlocked. Some attacks can end in death. Contrary to popular belief, this behaviour is intense territoriality and not a form of courtship display.

African Fish Eagles only spend 2 to 3 hours of the day hunting, usually from a waterside perch or, less often, from circling flight.

Most fish are caught 150-300 mm below the water surface in a graceful dive, with the feet thrust forward. They most often capture fish weighing from 1 to 3kg but are capable of catching fish up to 3.7 kg. Fish larger than this are usually scavenged. fish weighing more than 2.5kgs are not carried in flight but rather dragged to shore, using the wings as paddles.

The African Fish Eagle feeds primarily on fish but they are not limited to fish and will take a range of other prey from birds to mammals, reptiles, carrion, amphibians and termite alates. They are extremely agile and are able to take birds in flight.

The most frequent prey are surface-swimming fish such as tilapia (Cichlidae), catfish (Clarias spp) and mullet (Mugilidae).

Waterfowl and other birds up to the size of flamingos are commonly taken, especially young birds. African Fish Eagles are also known to feed on Red-billed Queleas at their breeding colonies, and they will raid breeding colonies of water birds like egrets, herons and cormorants, taking the eggs and nestlings.

Reptiles and mammals are less commonly captured. Reptile prey includes monitor lizards (Varanus spp), small Nile Crocodiles (Crocodylus niloticus) and terrapins. Mammalian prey includes hyraxes (Procavia spp), Vervet Monkey (Cercopithecus aethiops) and rodents.

The African Fish Eagle regularly feeds on carrion and can, on occasion, even be seen feeding at carcasses alongside vultures. They frequently resort to piracy and will steal a wide variety of prey from other birds such as kingfishers, pelicans, herons, storks, African Marsh Harrier, Western Osprey, Martial Eagle and Bateleurs.

Unlike most raptors, the African Fish Eagle is not known to cache its prey.

The African Fish Eagle breeds mainly from May to February in southern Africa. The African Fish Eagle is a monogamous, solitary nester. Mate fidelity is strong with pairs remaining together for many years or even decades. Courtship prior to breeding involves much duetting, with the pair flying over their territory together. The male may dive at the female who turns over to present her talons, but this does not involve territorial cartwheeling.

The nest is a large platform of sticks and is lined with grass, papyrus heads, other aquatic plants and, occasionally even weaver nests. Nests can measure up to 2m in diameter and reach over 2m high. Nests are usually constructed in a tall tree or on a cliff ledge, usually 12 to 15 m above the ground. Nests are generally situated less than 100m from water, but up to 2 km away when large trees are scarce. Nests may be used continuously for up to 24 years, but Pairs can often have 2 to 5 nests that they use in rotation.

From 1 to 4 (usually 2) white eggs are laid per clutch and eggs are laid at 2 or 3 day intervals. Incubation starts once the first egg has been laid, this results in the eggs hatching 2 or 3 days apart. The incubation period takes up to 45 days and is performed mainly by the female. Males will also incubate for short periods to allow the female to hunt.

Cainism (siblicide) is prevalent in the African Fish Eagle, even when food is abundant. The adults normally completely ignore sibling aggression. Despite this 2 or 3 young may sometimes survive to fledging. The nestling period lasts a further 70 to 75 days during which time the young are fed mostly by the female on food brought by the male. Fledged young are dependant on their parents for up to 60 days after their first flight.

Further Resources

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

The use of photographs by Andre Harmse, Andrew Keys, Ansie Dee Reis, Anthony Paton, Dave Rimmer, Desire Darling, Johan and Estelle van Rooyen, Lance Robinson, Malcolm Robinson, Neels Putter, Richard Johnstone and Salim Lee is acknowledged.

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

Other common names: Visarend (Afrikaans); iNkwazi (Zulu); Ingqolane, Unomakhwezana (Xhosa); Afrikaanse Zeearend (Dutch); Pygargue vocifère (French); Schreiseeadler (German); Águia-pesqueira-africana (Portuguese).

List of species available in this format.

Recommended citation format: Tippett RM 2024. African Fish Eagle Haliaeetus vocifer. Biodiversity and Development Institute. Available online at https://thebdi.org/2024/04/23/african-fish-eagle-haliaeetus-vocifer/

Bird identification, birding