Where eagles dare

0


As awe-inspiring in reality as in myth, eagles dominate African skies. Mike Unwin focuses on the remarkable adaptations of the continent’s species and suggests the best places to see them for yourself

Eagles are undeniably compelling. As predators, they occupy a similar ecological role to that of cats and other earthbound mammals, using supreme hunting prowess and a formidable array of weaponry to capture an enormous variety of prey. Such powers have long imbued them with emblematic status in human culture, from the golden eagle standard of imperial Rome to the bald eagle seal of the USA. The African fish eagle alone is the national symbol of five nations.

Africa is home to 25 of some 69 eagle species now recognised worldwide. All belong to the Accipitridae family of diurnal raptors, alongside the likes of buzzards, kites and vultures. They range from the martial eagle, which may top 6kg and can kill a small antelope, to the pigeon-sized but no less rapacious booted eagle, which captures birds in flight.

Some eagles are specialists: snake eagles, for example, have thickly scaled legs as protection against the bites of their serpent prey, while the African fish eagle has sharpened scales on its feet to help grip its slippery catch. Others are generalists: the tawny eagle hunts birds and mammals, but also scavenges carrion and will gorge on termites when swarms appear with the rains. Hunting technique also reflects habitat: thus bateleur eagles spend hours aloft as they comb the savannah for prey, but the long-crested eagle spends just as long stationary on a perch, waiting for rodents to appear in the grass below.

When it comes to breeding, eagles work harder than many birds. Pairs — in which females are considerably larger (up to 30 per cent heavier in some species) — form life-long, monogamous bonds, renewing their vows at the start of each breeding season with spectacular aerial displays. Nests can be huge: over 2m deep in the crowned eagle. Many species raise just a single chick, and parents invest heavily in child care: a crowned eagle youngster may remain with its parents for 18 months. Maturation is slow — at least five years for most, with multiple plumage changes along the way. But some eagles may live for more than 40 years in the wild.

Africa’s eagles occur in every habitat except the remotest areas of desert. The rainy season is an especially good time for eagle watching, when Eurasian migrants such as steppe eagles join the African resident species. Reserves and game parks, with their proliferation of prey, offer the easiest sightings: on a standard game drive in the likes of the Kruger, Okavango or Serengeti you could easily see at least five or six different species.

Outside protected areas, however, many eagles are struggling — the victims of habitat loss, which depletes both nest sites and prey, and persecution, with some farmers setting poisoned bait for anything they feel threatens their livestock. Several species are now very rare. The Madagascar serpent eagle, which inhabits the forest under-storey and feeds predominantly on reptiles and amphibians, was thought extinct for nearly 40 years before rediscovery in 1997. Today, there are believed to be no more than 100 breeding pairs.

Five eagle hotspots

1 Matobo Hills, Zimbabwe: Known for its dense population of Verreaux’s eagles, as well as African fish eagles on the dams and crowned eagles in the wooded valleys.
2 Kalagadi Transfrontier Park, South Africa/Botswana: Excellent raptor watching in very open terrain. Good for spotting bateleur, martial and black-chested snake eagles.
3 Lake Nakuru National Park, Kenya: Diverse habitats mean numerous species, from African fish eagles on the lake to tawny eagles on the savannah and long-crested eagles in the woodland edges.
4 Kruger Park, South Africa: Home to all the classic savannah species. Migrant ‘brown eagles’ (steppe, lesser-spotted and Wahlberg’s) gather during the rains. Easy self-drive makes this an excellent park in which to spend time on eagles.
5 South Luangwa National Park, Zambia: All the usual savannah species; plus abundant African fish eagles along the river and western banded-snake eagles in riverine forest.

10 African eagles

1 African fish eagle (Haliaeetus vocifer) (pictured above)
Large, with conspicuous black, white and chestnut plumage. Common on lakes and waterways across Africa. Signature ringing call, often given by pairs in duet, is hailed as the ‘sound of Africa’. Fishes from waterside perch, plucking prey from surface with lunging talons. Also hunts waterfowl, and often pirates food from other birds such as the goliath heron. An experienced adult needs only 10 minutes hunting per day to meet its nutritional needs.

2 Martial eagle (Polemaetus bellicosus)
Africa’s largest eagle, on average, with a wingspan that may reach 2.2m. A savannah species that takes guinea fowl, monitor lizards and mammals up to the size of small antelope. In soaring flight, shows broad, vulture-like wings, and white belly that contrasts with otherwise dark underside. Immature paler, with white head. Widespread but nowhere common. Often perches in very top of acacia, showing short crest. Declining in all but protected areas.

3 Booted eagle (Hieraaetus pennatus)
Small eagle that appears from October to March; migrant from Europe but also has separate resident population in south-west. Inhabits hilly regions, from arid country to woodland. Two colour phases: one all-brown; the other pale below. Captures birds in dashing aerial pursuit and small mammals on ground.

4 Long-crested eagle (Lophaetus occipitalis)
All-dark medium-sized eagle identified by long, floppy crest. Found in well-watered woodland areas, often beside clearings or along road verges. Feeds largely on small rodents. Perches in dead trees or on telegraph poles, dropping onto prey below. In flight, shows striking white primary patches on its wings.

5 Bateleur (Terathopius ecaudatus)
Medium-sized species, related to snake eagles. In flight, shows short tail, big head, long wings and tilting action. Adult has red face with harlequin plumage of black, white and chestnut. Juvenile all-brown but shares adult’s diagnostic shape. Wing tips project beyond tail when perched. Takes variety of prey and sometimes scavenges. Reputedly an expert at locating treed leopard kills. Found in savannah and open woodland, spending hours on the wing.

6 Tawny eagle (Aquila rapax)
Medium-large eagle, the most common of several brown species found across Africa’s savannah and woodland regions. Has a variety of plumages, from chocolate to sandy. A versatile predator, taking everything from insects to game birds and small mammals. Also scavenges, often joining vultures at a carcass. The similar steppe eagle, a winter visitor from Eurasia, can be distinguished by its generally darker plumage and longer yellow gape.

7 African hawk eagle (Aquila spilogaster)
Medium-sized eagle with dark upperparts and white underside. Widespread in woodland habitats, where often seen in pairs. A rapacious predator, capturing birds and mammals from guinea fowl to scrub hares, both on the ground and among trees. In soaring flight, shows contrasting black and white underwings.

8 Verreaux’s eagle (Aquila verreauxii)
Very large species, known in southern Africa as black eagle and closely related to golden eagle of northern hemisphere. All-black, except for white rump, white ‘V’ on back, and bright yellow feet and bill. In flight, shows pale primary patches and distinctive wing shape, bulging out from a narrow base. Lives only in mountainous or rocky terrain, feeding mostly on hyraxes, which it captures by flying low over hillsides. Pairs often soar and hunt together.

9 Crowned eagle (Stephanoaetus coronatus)
Almost as big as martial eagle but with shorter wings as adaptation to forest hunting. Widespread but elusive, frequenting tropical rainforest and woodland with large trees. Plumage heavily barred, with crested head and chestnut underwings. Formidable predator, using massive talons to capture monkeys in forest canopy. Also takes large birds, plus terrestrial mammals up to size of duiker and even domestic cats.

10 Brown snake eagle (Circaetus cinereus) 
Largest of five snake eagle species. All-brown, with large owl-like head, bare legs and piercing yellow eye. Widespread in woodland savannah regions. Perches conspicuously in bare trees, scanning ground for prey. Swoops on snakes and other reptiles. May tackle 1.5m mambas and cobras. In flight, shows paler underwings than other brown eagles.

Share.