Species of bird
 ;templatestyles src="Template:Taxobox/core/styles.css" / ;
The martial eagle (Polemaetus bellicosus) is a large eagle native to sub-Saharan Africa. It is the only member of the genus Polemaetus. A species of the booted eagle subfamily (Aquilinae), it has feathers over its tarsus. One of the largest and most powerful species of booted eagle, it is a fairly opportunistic predator that varies its prey selection between mammals, birds and reptiles. It is one of few eagle species known to hunt primarily from a high soar, by stooping on its quarry. This species, an inhabitant of wooded belts of otherwise open savanna, has shown a precipitous decline in the last few centuries due to a variety of factors. The martial eagle is one of the most persecuted bird species in the world. Due to its habit of taking livestock and regionally valuable game, local farmers and game wardens frequently seek to eliminate martial eagles, although the effect of eagles on this prey is almost certainly considerably exaggerated. Currently, the martial eagle is classified with the status of Endangered by the IUCN.""
Range.
The martial eagle can be found in most of sub-Saharan Africa, wherever food is abundant and the environment favourable. With a total estimated distribution of about , it has a substantial distribution across Africa, giving it a somewhat broader range than other species there like the crowned eagle ("Stephanoaetus coronatus") and the Verreaux's eagle ("Aquila verreauxii"). Although never common, greater population densities do exist in southern Africa and in some parts of east Africa. Martial eagles tend to be rare and irregular in west Africa but are known to reside in Senegal, The Gambia and northern Guinea-Bissau, southern Mali and the northern portions of Ivory Coast and Ghana. From southern Niger and eastern Nigeria the species is distributed spottily through Chad, Sudan and the Central African Republic as well as the northern, eastern, and southern portions of the Democratic Republic of the Congo. In east Africa, they range from Somaliland and Ethiopia more or less continuously south through Kenya, Uganda, Tanzania and in southern Africa from Angola, Zambia, Malawi and southern Mozambique to South Africa. Some of the larger remaining populations are known to persist 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.
Taxonomy.
The Accipitridae family (hereafter accipitrids) is by far the most diverse family of diurnal raptors in the world, with more than 230 currently accepted species. As a member of the booted eagle subfamily, Aquilinae, the martial eagle is one of the roughly 15% of extant species in the family to have feathers covering its legs. This helps distinguish these species from other eagles and raptors, as they are present even in tropical species such as the martial eagle. Under current classifications, booted eagles consist of approximately 38 living species that are distributed in every continent inhabited by the accipitrids, which excludes only the continent of Antarctica. Just under half of the living species of booted eagle are found in Africa. Studies have been conducted on the mitochondrial DNA of most booted eagle species, including the martial eagle, to gain insight on how the subfamily is ordered and which species bear relation to one another. DNA testing in the 1980s indicated the martial eagle was a specialized off-shoot of the small-bodied "Hieraaetus" eagles, and one study went so far as to advocate that the martial eagle be included in the genus. However, more modern and comprehensive genetic testing has shown that the martial eagle is distinct from other living booted eagles and diverged from other extant genera several million years ago. Genetically, the martial eagle fell between two other species in monotypical genera, the African long-crested eagle ("Lophaetus occipitalis") and the Asian rufous-bellied eagle ("Lophotriorchis kienerii"), that similarly diverged long ago from other modern species. Given the disparity of this species' unique morphology and the fact that the two aforementioned most closely related living species are only about as large as the bigger buzzards, the unique heritage of the martial eagle is evident. 
There are no subspecies of martial eagle, and the species varies little in appearance and genetic diversity across its distribution.
Description.
The martial eagle is a very large eagle. In total length, it can range from , with an average of approximately . Its total length – in comparison to its wingspan – is restricted by its relatively short tail. Nonetheless, it appears to be the sixth or seventh longest extant eagle species. The wingspan of martial eagles can range from . Wingspans of as much as have been reported but may be unsubstantiated. Average wingspans have been claimed of and for the species, however ten measured martial eagles in the wild were found to average in wingspan. Thus, the martial eagle appears to average fourth in wingspan among living eagles, behind only the Steller's sea-eagle ("Haliaeetus pelagicus"), the white-tailed eagle ("Haliaeetus albicilla") and the wedge-tailed eagle ("Aquila audax"), in roughly that order. For a species that is fairly homogeneous in its genetic make-up, the body mass of martial eagles is surprisingly variable. To some extent, the variation of body masses in the species is attributable to considerable reverse sexual dimorphism as well as varying environmental conditions of various eagle populations. Unsexed martial eagles from various studies have been found to have weighed an average of in 17 birds, in 20 birds and in 20 birds while the average weight of martial eagles shot by game wardens in the early 20th century in South Africa was listed as . In weight range, the martial eagle broadly overlaps in size with the golden eagle ("Aquila chrysaetos") and Verreaux's eagle (and is even exceeded by them in maximum known body mass). Based on numerous studies, the martial eagle appears to be mildly heavier than the Verreaux's eagle but (derived from the globally combined body mass of its various races), the mean body masses of golden and martial eagles are identical at approximately . This renders the golden and martial eagles as tied as the largest African eagles (by body mass but not in total length or wingspan, in which the martial bests the golden), as well as the heaviest two species of booted eagle in the world and as tied as the sixth heaviest eagles in the world, after the three largest species of sea eagle (Steller's being the heaviest extant, the others ranking 4th and 5th), the harpy eagle ("Harpia harpyja") and the Philippine eagle ("Pithecophaga jefferyi"). The longest African eagle (and second longest booted eagle after the wedge-tailed eagle ("Aquila audax")) is the crowned eagle by virtue of its relatively longer tail, as its body weight is slightly less than these three heaviest booted eagle species.
Sexual dimorphism.
Martial eagles are highly sexually dimorphic. While females average about 10% larger in linear dimension, in body mass, the sexual dimorphism of martial eagles is more pronounced. Males reportedly can weigh from . Seven males in southern Africa averaged and five in another dataset averaged . Twelve adult males in Maasai Mara, Kenya averaged . Meanwhile, females can weigh from . In southern Africa, seven females averaging . Elsewhere, a claim was made of an average of almost certainly describes a sample entirely of female specimens. In the Maasai Mara, 7 females averaged . Reports of males weighing as much as and females weighing as little as are known but may possibly represent individual eagles misidentified by sex, which is reportedly not infrequent due to mistakes in the field. Thus the dimorphism by weight is roughly 36% in favor of the female, which is unusually out-of-sync with the linear differences between the sexes. For example, the greater spotted eagle ("Clanga clanga"), the most sexually dimorphic booted eagle overall with a linear difference between the sexes of 20%, has around the same level of sexual dimorphism by body mass as the martial eagle which show about half as much linear dimorphism. In standard measurements, male martial eagles measure in wing chord size, in tail length and in tarsus length. Meanwhile, females measure in wing chord, in tail length and tarsal length. Overall, the bulk and much more massive proportions of females, which include more robust feet and longer tarsi, may at times allow experienced observers to sex lone birds in the wild.
Colouring and field identification.
The adult's plumage consists of dark brown coloration on the upperparts, head and upper chest, with an occasional slightly lighter edging to these feathers. The dark feathers can appear grayish, blackish or even plum-colored depending on lighting conditions. The body underparts are feathered white with sparse but conspicuous blackish-brown spotting. The underwing coverts are dark brown, with the remiges being pale streaked with black, overall imparting the wings of adults a dark look. The underside of the tail has similar barring as the remiges while the upperside is the same uniform brown as the back and upperwing coverts. The eyes of mature martial eagles are rich yellow, while the cere and large feet pale greenish and the talons black. Martial eagles have a short erectile crest, which is typically neither prominent nor flared (unlike that of the crowned eagle) and generally appears as an angular back to a seemingly flat head. This species often perches in a quite upright position, with its long wings completely covering the tail, causing it be described as "standing" rather than "sitting" on a branch when perched. In flight, martial eagles bear long broad wings with relatively narrow rounded tips that can appear pointed at times depending on how the eagle is holding its wings. It is capable of flexible beats with gliding on flattish wings, or slightly raised in a dihedral. This species often spends a large portion of the day on the wing, more so than probably any other African eagles, and often at a great height. Juvenile martial eagles are conspicuously distinct in plumage with a pearly gray colour above with considerable white edging, as well as a speckled grey effect on crown and hind neck. The entire underside is conspicuously white. The wing coverts of juveniles are mottled grey-brown and white, with patterns of bars on primaries and tail that are similar to adult but lighter and greyer. In the fourth or fifth years, a very gradual increase to brownish feather speckling is noted but the back and crown remain a fairly pale grey. At this age, there may be increasing spots on throat and chest which coalesce into a gorget and some spots on abdomen may variably manifest as well. The eyes of juveniles are dark brown. This species reaches adult plumage by its seventh year with the transition to adult plumage happening quite rapidly after many years in a little-changing juvenile plumage.
There are a few serious identification challenges for the species. The black-chested snake eagle ("Circaetus pectoralis") is similar in overall colouring (despite its name it is brown on the chest and the back, being no darker than the adult martial eagle) to martial eagles but is markedly smaller, with a more prominent, rounded head with large eyes, plain, spotless abdomen, bare and whitish legs. In flight, the profile of the snake eagle is quite different, with nearly white (rather than dark brown) flight feathers and much smaller, narrower wings and a relatively larger tail. For juveniles, the main source for potential confusion is the juvenile crowned eagle, which also regularly perches in an erect position. The proportions of crowned eagles are quite distinct from martial eagles as they have much shorter wings and a distinctly longer tail. The juvenile crowned eagle has a whiter head, more scaled back, and spotted thighs and legs lacking in the martial eagle. Beyond their distinct flight profile by wing and tail proportions, crowned eagles have whiter and more obviously banded flight-feathers and tail. Other large immature eagles in Africa tend to be much darker and more heavily marked both above and below than martial eagles.
Predatory physiology.
Martial eagles have been noted as remarkable for their extremely keen eyesight (3.0–3.6 times human acuity), partly due to their eye being nearly as large as a human's eye. Due to this power, they can spot potential prey from a great distance, having been known to be able to spot prey from