The adult's plumage consists of dark grey-brown coloration on the upperparts, head and upper chest, with slightly lighter edging to these feathers. The body underparts are white with blackish-brown spotting. The underwing coverts are brown, with pale flight feathers being streaked with black. The female is usually larger and more spotted than the male. The immature is paler above, often whitish on the head and chest, and has less spotted underparts. It reaches adult plumage in its seventh year. Martial eagles have a short erectile crest, which is often not prominent. It often perches in a quite upright position, with its long wings completely covering the tail. The bill, at 5.5 cm (2.2 in), is strong and the legs are feathered to the heavy, powerful feet. There are few serious identification challenges for the species. The black-chested snake eagle is smaller, with a relatively more prominent head and white lining the flight feathers. The crowned eagle, which also regularly perches in an erect position, has distinctly shorter wings and a distinctly longer tail and, though its plumage is fairly variable, it is more scaled on the back and it has distinctive barring on the underparts and the wings. More so than any other African eagle, the martial eagle is often seen only in flight. Martial eagles have been noted as remarkable for their extremely keen eyesight (3.0?3.6 times human acuity). Due to this power, they can spot potential prey from a very great distance. The martial eagle is a very large eagle, with a length of 78?96 cm (31?38 in), weight of 3?6.2 kg (6.6?13.7 lb) and a wingspan of 188?260 cm (6 ft 2 in?8 ft 6 in). This is the largest eagle in Africa and is the fifth heaviest (on average) eagle in the world.
Habitat and Distribution
Its preferred habitat is open woods and woodland edges, wooded savannah and thornbush habitats. It is not found in dense tropical forests such as the Guinean and Congolian forests, but needs trees to nest in and to use for obstruction while hunting. In southern Africa, they have adapted to more open habitats, such as semi-desert and open savanna with scattered trees, wooded hillocks and, as a recent adaptation, around pylons. They usually seem to prefer desolate or protected areas. The martial eagle can be found in most of sub-Saharan Africa, wherever food is abundant and the environment favourable. It is never common, but greater population densities do exist in southern Africa, especially in Zimbabwe and South Africa. Generally, these birds are more abundant in protected areas such as Kruger National Park and Kgalagadi Transfrontier Park in South Africa, or Etosha National Park in Namibia.
Among bird prey, martial eagles often choose to predate medium-sized ground-dwelling species such as francolins, guineafowl or bustards. Other birds predated have included young ostriches, storks, herons, other waterfowl, hornbills and quelea flocks. At one eyrie, the remains of six spotted eagle-owls were counted. Martial eagle occasionally prey upon adult Kori bustard, which are possibly the heaviest flying animal alive today. In some areas mammals constitute the greater part of the diet than birds or reptiles. Among regular mammal prey are hares, hyraxes, mongooses, squirrels, springhares, rats, genets, foxes, baboons, other monkeys, young warthogs, dikdiks, young impala, and various other young or small antelope. Large and formidable prey are not unheard of, with carnivores such as caracal, servals and black-backed jackals having been killed by this eagle. Martial eagles have predated adult duikers weighing up to 37 kg (82 lbs), perhaps the heaviest live prey item recorded for any wild raptor. Oversized prey, being any that are notably heavier than the eagle itself, are returned to repeatedly after the kill for feeding by both members of a breeding pair, since it is too heavy to take flight with or carry in flight. However, most prey items weigh under 5 kg (11 lb). Martial eagles may additionally attack domestic livestock, including poultry, lambs and young goats, but this is never a great part of the diet
Martial eagles may breed in various months in different parts of their range. The mating season is in November through April in Senegal, January to June in Sudan, August to July in northeast Africa and almost any month in eastern Africa, though mostly in April?November. Martial eagles have been thought to have no distinctive display flight, but they do engage in a subtle one, with the males flying mildly around in circles. Rarely, the female joins him and the pair grasp talons with each other. They build their nests in large trees, often placing them in the main fork of tree at 6?20 m (20?66 ft) off the ground, though nests have been recorded from 5 to 70 m (16 to 230 ft) high, in the highest cases on top of the tree canopy. Often trees used are on the sides of cliffs, ridges, valley or hilltop, with one nest having been found within a cave. In the karoo of South Africa, they have also nested on electric-power pylons. The nest is a huge construction of sticks. In the first year of construction, the nest is 1.2 to 1.5 m (3.9 to 4.9 ft) in diameter and 0.6 m (2.0 ft) deep. After regular use over several years, the nests can regularly measure in excess of 2 m (6.6 ft) in both diameter and depth. Martial eagles have a slow breeding rate, laying usually one egg (rarely two) every two years. The egg is incubated for 45 to 53 days and the chick fledged at 96 to 104 days. Despite increasing signs of independence (such as flight and beginning to practice hunting), juvenile birds will remain in the care of their parents for a further 6 to 12 months. Due to this long dependence period, these eagles can usually only mate in alternate years.
Calls and Songs
During the breeding season, these typically silent birds utter a loud cry klee-klee-klee-kloeee-kloeee-kuleee.