martial eagle

The martial eagle (''Polemaetus bellicosus'') is a large eagle native to sub-Saharan Africa.Ferguson-Lees & Christie, ''Raptors of the World''. Houghton Mifflin Company (2001), . It is the only member of the genus ''Polemaetus''. A species of the booted eagle subfamily (Aquilinae), it has feathering 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.Steyn, P. (1983). ''Birds of prey of southern Africa: Their identification and life histories''. Croom Helm, Beckenham (UK). 1983. An inhabitant of wooded belts of otherwise open savanna, this species 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.''Simmons, R.E. (2005). ''Martial Eagle Polemaetus bellicosus''. Roberts’ Birds of southern Africa, 7th edition. Hockey, PAR, Dean, WRJ and Ryan, PG (eds), 538-539.Cloete, D. (2013). ''Investigating the decline of the Martial Eagle (Polemaetus bellicosus) in South Africa''. University of Cape Town.''

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'').BirdLife International (2017) IUCN Red List for birds. Downloaded from
/ref> 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 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.Boshoff, A.F. ''Martial eagle Polemaetus bellicosus''. In: Harrison JA, Allan DG, Underhill LG, Herremanns M, Tree AJ, Parker V, Brown CJ, editors. The atlas of southern African Birds, vol 1. (1997). Randburg: BirdLife South Africa. 192-3.

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.Kemp, A.C. (1994). ''Martial Eagle (Polemaetus bellicosus)''. Pp. 200-201 in: del Hoyo, Elliott & Sargatal. eds. (1994). Handbook of the Birds of the World, vol. 2. 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.Brown, L. & Amadon, D. (1986). ''Eagles, Hawks and Falcons of the World''. The Wellfleet Press. . 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.Amadon, D. (1982). ''The genera of booted eagles: Aquila and relatives''. Journal of the Yamashina Institute for Ornithology, 14(2-3), 108-121.Lerner, H., Christidis, L., Gamauf, A., Griffiths, C., Haring, E., Huddleston, C.J., Kabra, S., Kocum, A., Krosby, M., Kvaloy, K., Mindell, D., Rasmussen, P., Rov, N., Wadleigh, R., Wink, M. & Gjershaug, J.O. (2017). ''Phylogeny and new taxonomy of the Booted Eagles (Accipitriformes: Aquilinae)''. Zootaxa, 4216(4), 301-320. 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.Lerner, H.R., & Mindell, D.P. (2005). ''Phylogeny of eagles, Old World vultures, and other Accipitridae based on nuclear and mitochondrial DNA''. Molecular Phylogenetics and Evolution, 37(2), 327-346. 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 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 .Redman, N., Stevenson, T., & Fanshawe, J. (2010). ''Birds of the Horn of Africa: Ethiopia, Eritrea, Djibouti, Somalia and Socotra.'' Bloomsbury Publishing. 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.Mendelsohn, J.M., Kemp, A.C., Biggs, H.C., Biggs, R., & Brown, C.J. (1989). ''Wing areas, wing loadings and wing spans of 66 species of African raptors''. Ostrich, 60(1), 35-42.Saito, K. (2009). ''Lead poisoning of Steller’s Sea-Eagle (Haliaeetus pelagicus) and White-tailed Eagle (Haliaeetus albicilla) caused by the ingestion of lead bullets and slugs''. Hokkaido Japan. In RT Watson, M. Fuller, M. Pokras, and WG Hunt (Eds.). Ingestion of Lead from Spent Ammunition: Implications for Wildlife and Humans. The Peregrine Fund, Boise, Idaho, USA. 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.Biggs, H.C., Kemp, A.C., Mendelsohn, H.P. & Mendelsohn, J.M. (1979). ''Weights of South African Raptors and Owls''. Durban Museum Novitates, 12: 73-81. 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 .Bright, J.A., Marugán-Lobón, J., Cobb, S.N., & Rayfield, E.J. (2016). ''The shapes of bird beaks are highly controlled by nondietary factors''. Proceedings of the National Academy of Sciences, 113(19), 5352-5357.Stevenson-Hamilton, J. (1954). ''Wild life in South Africa''. Cassell and Co., London. 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 appear to average 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 . The 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 .Musindo, P.T. (2012). ''Morphological variation in bills and claws in relation to Prey type in Southern African Birds of Prey (Orders Falconiformes and Strigiformes)''. Thesis, University of Zimbabwe.van Eeden, R., Whitfield, D.P., Botha, A., & Amar, A. (2017). ''Ranging behaviour and habitat preferences of the Martial Eagle: Implications for the conservation of a declining apex predator''. PLoS ONE, 12(3), e0173956. Twelve adult males in Maasai Mara, Kenya averaged .Hatfield, R. S. (2018). ''Diet and Space Use of the Martial Eagle (Polemaetus bellicosus) in the Maasai Mara Region of Kenya''. Theses and Dissertations--Forestry and Natural Resources. 44. 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.Smeenk, C. (1974). ''Comparative-ecological studies of some East African birds of prey''. Ardea 62 (1-2) : 1-97. 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 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 as far as away. Their visual acuity may rival some eagles from the genus '' Aquila'' and some of the larger falcons as the greatest of all diurnal raptors. The talons of martial eagles are impressive and can approach the size, especially in mature females, of those of the crowned eagle despite their slenderer metatarsus and toes compared to the crowned species. Accipitrids usually kill their prey with an elongated, sharp hind toe claw, which is referred to as the hallux claw and is reliably the largest talon in members of the accipitrid family. The average length of the hallux claw in unsexed martial eagles from Tsavo East National Park, Kenya was found to be . In comparison, the average hallux claw of a large sample of golden eagles was similar at . Meanwhile, the three largest clawed modern eagles were found to measure as such: in small samples, the Philippine eagle and crowned eagle had an average hallux claw length of and , respectively, and harpy eagles have an average hallux claw length of approximately . A further sample of martial eagles averaged in 6 males and in 7 females, with the median between the sexes being , these being the largest talons of all booted eagles behind only the crowned eagle. The inner claw on the front of the foot of the martial eagle is especially sizeable proportional to other extremities and unusually can approach, if not reach, the same size as the hallux claw. This inner claw was found to average , in comparison to that of the crowned eagle which measures . The tarsus is quite long in martial eagles, the fourth longest of any living eagle and the longest of any booted eagle species, seemingly an adaptation to prey capture in long grass, including potentially dangerous prey. The bill is of medium size relative to that of other large eagles, with a mean culmen length from Tsavo East of . The bill is larger than the average bill of the large members of the genus '' Aquila'' but is notably smaller than those of the large species of sea eagle and the Philippine eagle. The gape size of martial eagles is relatively large, however, being proportionally larger than in other booted eagle species behind (albeit considerably behind) the Indian spotted eagle (''Clanga hastata'') and the steppe eagle (''Aquila nipalensis'') in relative gape size, indicating a relative specialization towards swallowing large prey whole.

Voice

The martial eagle is a weak and infrequent vocaliser. Little vocal activity has been reported even during the breeding season. The recorded contact call between pair-members consists of the birds, usually when perched, letting out a low mellow whistle, '. More or less the same vocalisation is known to have been uttered by females when male brings food and repeated mildly by large begging young. During territorial aerial display and sometimes when perched, adults may utter a loud, trilling '. The territorial call may be heard from some distance. Recent fledglings also at times make this call. A soft ' may be heard, made by pairs around their nest, perhaps being a mutual contact call. In comparison, the crowned eagle is highly vocal especially in the context of breeding.

Habitat

The martial eagle is to some degree adaptable to varied habitats but shows an overall preference for open woods and woodland edges, wooded savannah and thornbush habitats. The martial eagle has been recorded at elevations of up to but is not a true mountain dwelling species and resident eagles do not usually exceed an elevation of . These eagles also avoid closed-canopy forests and hyper-arid desert. As such it is mostly absent from Guinean and Congolian forests, despite the species’ requirement for large trees for nesting purposes. It is shown that martial eagles can inhabit forests locally in areas where openings occur. For example, in a bird atlas for the country of Kenya, perhaps surprisingly, 88% of martial eagles were found to reside in well-wooded areas and they occurred in areas where annual rainfall exceeded . In southern Africa, they have adapted to seemingly more open habitats than elsewhere in their range, such as semi-desert and open savanna with scattered trees, wooded hillocks and, as a recent adaptation, around pylons. In the desert areas of Namibia, they utilize ephemeral rivers that flow occasionally and allow large trees to grow. They usually seem to prefer desolate or protected areas. In the Karoo of South Africa, they consistently avoid areas with moderate to heavy cultivation or with heavier or more consistent winter rainfall.Machange, R.W., Jenkins, A.R., & Navarro, R.A. (2005). ''Eagles as indicators of ecosystem health: Is the distribution of Martial Eagle nests in the Karoo, South Africa, influenced by variations in land-use and rangeland quality?'' Journal of Arid Environments, 63(1), 223-243. One study on the occurrence of diurnal raptors in protected areas against unprotected areas found that martial eagle detection was nearly twice as frequent in protected areas during the dry season and more than three times as frequent during the wet season than in unprotected areas.

Behaviour

The martial eagle spends an exceptional amount of the time in the air, often soaring about hill slopes high enough that binoculars are often needed to perceive them. When not breeding, both mature eagles from a breeding pair may be found roosting on their own in some prominent tree up to several miles from their nesting haunt, probably hunting for several days in one area, until viable prey resources are exhausted, and then moving on to another area. However, martial eagles, especially adult birds, are typically devoted to less disturbed areas, both due to these typically offering more extensive prey selection and their apparent dislike for a considerable human presence. Martial eagles tend to be very solitary and are not known to tolerate others of the own species in the area outside of the pair during the breeding season. In general this species is more shy towards humans than other big eagles of Africa, but may be seen passing over populated country at times. The most frequently seen type of martial eagle away from traditional habitats are presumed nomadic subadults. One individual that was ringed as subadult was recovered 5.5 years later away from the initial banding site. Another martial eagle ringed as a nestling was found to have moved in 11 months.

Dietary biology

The martial eagle is one of the world's most powerful avian predators. Due to both its underside spotting and ferocious efficiency as a predator it is sometimes nicknamed “the leopard of the air”. The martial eagle is an apex predator, being at the top of the avian food chain in its environment. In its common, scientific and most regional African names, this species name means “war-like” and indicates the force, brashness and indefatigable nature of their hunting habits. The aggressiveness of the hunting martial eagle, which may rival that of the overall behaviorally bolder crowned eagle, can seem incongruous with their other behaviours, as it otherwise is considered a shy, wary and evasive bird. Martial eagles have been seen to charge at much larger adult ungulates and rake at their heads and flanks, at times presumably to separate the mammals from their young so they can take the latter with more ease. At other times, these eagles will set down upon a wide range of potentially dangerous prey including other aggressive predators in broad daylight, such as monitor lizards, venomous snakes, jackals and medium-sized wild cats. Adult eagles tend to hunt larger, potentially dangerous prey more often than immature ones, presumably as they refine their hunting skills with maturity. The martial eagle hunts mostly in flight, circling at a great height anywhere in its home range. When prey is perceived with their superb vision, the hunting eagle then stoops sharply to catch its prey by surprise with the prey often being unable to perceive the eagle at nearly as far as the eagle can perceive them despite often being in the open. The martial eagle tends to hunt in a long, shallow stoop; however, when the quarry is seen in a more enclosed space, it parachutes down at a steeper angle. The speed of descent is controlled by the angle at which the wings are held above the back. At the point of impact, it shoots its long legs forward, often killing victims on impact, somewhat as large falcons often dispatch their prey. Prey may often be spotted from away with a record of about . On occasion, they may still-hunt from a high perch or concealed in vegetation near watering holes. If the initial attempt fails, they may swoop around to attempt again, especially if the intended victim is not dangerous. If the quarry is potentially hazardous, such as mammalian carnivores, venomous snakes or large ungulates, and becomes aware of the eagle too soon, the eagle tends to abandon the hunt. Unusually for a bird of its size, it may rarely hover while hunting. This hunting method may be employed particularly if the quarry is any of the aforementioned potentially dangerous prey items such as venomous snakes or carnivores. Other large eagles may similarly (if infrequently) hover over prey such as canids and then quickly drop onto if the quarry makes the mistake of pointing its dangerous mouth downwards, then gripping its victim on the back while controlling the neck with the other foot until blood loss is sufficient to kill the prey. Prey, including birds, are generally killed on the ground, with infrequent reports of prey taken from trees. Some larger (and presumably slower-flying) avian prey may be taken while in flight; victims of successful hunts have consisted of water birds such as herons, storks and geese. If kills are too large and heavy to carry in flight, both members of a pair may return to the kill over several days, probably roosting nearby. If nesting, the pair tends to dismember pieces of large kills such as limbs to bring to the nest. Much of the large prey, perhaps most, that is left on the ground is lost to scavengers.

The diet of the martial eagle varies greatly with prey availability and can be dictated largely by opportunity. Remarkably, mammals, birds and reptiles can in turn dominate the prey selection of martial eagles in a given area, with no one prey type globally dominating their prey spectrum. In some areas, both mammals and birds can each comprise more than 80% of the prey selection.Boshoff, A.F., & Palmer, N.G. (1980). ''Macro-analysis of prey remains from martial eagle nests in the Cape Province''. Ostrich, 51(1), 7-13. Over 170 prey species have been reported for the martial eagle which is a much higher number than the full prey spectrum of other larger African booted eagles, and even this may neglect some of the prey they take in the little studied populations from west and central Africa and the northern part of east Africa.Brown, L. (1977). ''Eagles of the World''. Universe Books. Prey may vary considerably in size but for the most part, prey weighing less than are ignored by hunting martial eagles, with only about 15% of the known prey species averaging less than this. A majority of studies report the average size of prey for martial eagles being between .Boshoff, A.F., Palmer, N.G., & Avery, G. (1990). ''Regional variation in the diet of martial eagles in the Cape Province, South Africa''. S. Afr. J. Wildl. Res, 20, 57-68. Average weight of prey taken has been reported at as low as .Hauser, M.D. (1996). ''The Evolution of Communication''. MIT Press, Cambridge, MA. A food study largely based in data from the Great Rift Valley, Kenya, as well as from Maasai Mara, did reinforce a mean prey mass of just over for the species.Manuel, H. (2020). ''Nesting martial eagle (Polemaetus bellicocus) diet: Influence of prey delivery and diversity in two Kenyan ecosystems''. Biological baseline study. However, the mean prey body mass is considerably higher in other known dietary studies. In by far the largest dietary study thus far conducted for the martial eagle species (in the Cape Province, South Africa) the estimated mean prey body mass was approximately . In Tsavo East National Park of Kenya, the mean estimated body mass of prey was quite similar at approximately . Average prey weights in a study of the Maasai Mara was seemingly even higher, at a median between the average prey sizes for each sex of martial eagle at approximately . Despite perhaps a majority of prey for this species weighing less than , martial eagles regular prey size range is claimed at up to .Mooring, M.S. (1993). ''Predation on a newborn impala by a martial eagle''. Ostrich, 64(4), 185-186. There is some evidence of prey partitioning (which can be potentially delineated both by prey species and body size of prey items taken) between the sexes. This is typical of raptors with pronounced size sexual dimorphism, as is the case in martial eagles. For instance, in populations where large adult monitor lizards are significant as prey, they only start to appear in prey remains at nests only after the female resumes hunting in the latter part of the breeding season. The species was the focus for a study using web sourced photography to explore the species' diet across its African range, this study revealed new insight into difference in prey composition between regions, and also revealed differences in prey composition between adult and sub-adult birds, with adults found to prey more frequently on bird prey than sub-adults. The sexual dimorphism of kills was verified in studies from the Great Rift Valley and Maasai Mara. One study stated that the mean weight of male kills was and that of females was . In Maasai Mara, the mean prey was significantly higher for both males, at about , and for females, at about .

Mammals

The most diverse class of prey in the diet as known are mammals, with over 90 mammalian prey species reported. In the Cape Province, the cape hare (''Lepus capensis'') reportedly dominates the prey selection, comprising about 53% of the foods selected. Other lagomorphs, namely the slightly smaller Smith's red rock hare (''Pronolagus rupestris''), mildly larger African savanna hare (''Lepus microtis'') and the much larger scrub hare (''Lepus saxatilis''), are not infrequently taken both in and outside of the Cape area. In Maasai Mara, the most regularly identified food, at 17.3% of 191 prey items (and particularly for male martial eagles at 23.9% of their kills), was found to be comprised by a mixture of cape and scrub hares, these in total weighing an estimated mean of . For the most part rodents are ignored as prey as they are probably too small despite martial eagles taking at times appreciable numbers of Cape (''Xerus inauris'') and unstriped ground squirrels (''Xerus rutilus''). However, rodents selected as prey have ranged in size from the Southern African vlei rat