The Martial Eagle (Polemaetus bellicosus) is a large eagle found in open and semi-open habitats of sub-Saharan Africa. It is the only member of the genus Polemaetus.
The martial eagle is a very large eagle, with a length of 31–38 in, and a wingspan of 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.
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. 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 is strong and the legs are feathered to the heavy, powerful feet.
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 can be found in most of sub-Saharan Africa, wherever food is abundant and the environment favorable. It is never common, but greater population densities do exist in southern Africa. Generally, these birds are more abundant in protected areas.
The Martial Eagle is one of the world's most powerful avian predators and, among African raptors, only the crowned eagle is comparable in predatory dominance. The Martial Eagle is an apex predator, being at the top of the avian food chain in its environment and, if in healthy condition, having no natural predators. Although the ranges of the Martial and Crowned Eagles occasionally abut each other, the species have differing habitat preferences, with the crowned preferring denser forests as opposed to the wooded savanna preferred by the martial eagle, and the two are not known to compete directly.
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 predate 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 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.
The martial eagle is probably naturally scarce, due to its requirement for large territories and low reproductive rates. However, the species has been experiencing a major decline in numbers in recent years, due largely to being directly killed by humans. Its conservation status was uplisted to Near Threatened in 2009 and to Vulnerable in 2013 and another uplisting is already expected. In many areas where they come into contact with humans, eagle populations have decreased greatly through persecution via shooting and poisoning. The reasoning behind such persecution is that martial eagles are taken as a predatory threat to livestock. Despite this perception, in reality domestic animals constitute only a small proportion of the species' diet, whereas the presence of eagles is a sure sign of a healthy environment. Indirect threats, such as collision with power-lines, are also a common modern problem for martial eagles. Another hazard is caused by steep sided farm reservoirs, in which many birds drown. In South Africa, this eagle may have lost 20% of its population in the last three generations due to such collisions. Further excerbating the problems faced by the martial eagle, habitat destruction and reduction of prey continues to occur at a high rate outside of protected areas. The preservation of this species depends on education of farmers, and the increase of protected areas where the species can nest and hunt.