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.
[2] 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.
[3][28] 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.
[2][3][8] 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.
[3][54][55] 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.
[56][57] 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.
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.
[62] 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 1.2 kg (2.6 lb) for the species.
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 2.26 kg (5.0 lb).
[3][61][67] 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 2.54 kg (5.6 lb).
[3][32][79][80] These monkey species have special alarm calls, distinct from those uttered in response to the presence of for example a leopard (Panthera pardus), specifically for martial eagles.
[76][66][89] However, most of these types of mongoose are also relatively small, and can effectively escape quickly to the safety of their underground home, so the lighter, more nimble male martial eagle is more likely to habitually pursue them.
[64][106] Calves of the other antelope may also be included in their prey spectrum, including hartebeest (Alcelaphus buselaphus), bontebok (Damaliscus pygargus), common tsessebe (Damaliscus lunatus), springbok (Antidorcas marsupialis), Eudorcas gazelles, gerenuk (Litocranius walleri), bushbuck (Tragelaphus sylvaticus), grey rhebok (Pelea capreolus), kob (Kobus kob) and mountain reedbuck (Redunca arundinum).
[3][32][61][107][108][109][110][111] Additionally, piglets of warthogs (Phacochoerus africanus) (of which only the martial eagle among accipitrids is similarly mentioned as a significant predator) and bushpigs (Potamochoerus larvatus) are taken.
[4][116] However, one adult female duiker dispatched via strangulation weighed an estimated 37 kg (82 lb), one of the largest known raptorial kill for any species on the African continent.
[3][4][61] When attacking these ground-loving birds, which are understandably quite easily spooked and usually react to potential danger by flying off, martial eagles almost always try to take them on the ground much like they do mammalian prey.
One protracted battle resulted in an injured leg for the eagle and massive, fatal blood loss for the male bustard, which was ultimately scavenged by a jackal by the following morning.
[3][131][132] Short of three attacks on spotted thick-knees (Burhinus capensis), which weigh about 0.42 kg (15 oz), and smaller still crowned lapwings (Vanellus coronatus) so far as is known small waders or shorebirds are ignored as prey.
Due to great diversity of raptors present, each species have shown adaptive specializations, which may consist of various morphological differences that allow them to capitalize on distinct prey selection, hunting methods, habitat and/or nesting habits.
The crowned eagle dwells mainly in mature forests, building nests in large interior trees, and is primarily a perch-hunter, watching and listening for monkeys and other prey over a long period.
Considering their potential for aggressiveness in regards to prey pursuits, martial eagles often appear to be surprisingly passive in response to kleptoparasitism, especially if they are able to first fill their crop.
[2][9][114] In Kalahari Gemsbok National Park of South Africa, almost all nests were in the highly thorny, Acacia-like tree, Vachellia erioloba, in savanna areas.
Locally, with the sometimes epidemic levels of clear-cutting of old-growth trees, such pylons may provide a fairly suitable alternative that the eagles can utilize in absence of woodlands.
[2][3][9] Despite increasing signs of independence (such as flight and beginning to practice hunting), in extreme cases, juvenile birds may remain in the care of their parents for a further 6 to 12 months.
Breeding success is variable and is probably driven by a combination of factors, including prey supply, rainfall levels and distance from human activity.
[3][5][9][170] The immature eagle, with an average of about four years before it can expect its first breeding season, spends much of its time subsequent to its final separation from its parents looking for feeding opportunities and refining its hunting techniques.
[192] However, due to fact that they do not reproduce under normal circumstances until they are 6 to 7 years old and their sporadic, widely placed breeding attempts, makes the martial eagle an exceptionally unproductive bird with very low population replacement levels.
This does not take into account, that unlike previously thought, martial eagles do not disdain carrion and some birds, especially immature, are certain to attend carcasses of livestock at times, leading to them being mistaken as stock-killers.
[3] However, martial eagles will indeed at times kill not inconsiderable numbers of livestock, including goats and sheep (mostly young kids and lambs), chickens, most variety of pets, piglets and possibly newborn calves.
[202] Further exacerbating the problems faced by the martial eagle, habitat destruction and reduction of prey continues to occur at a high rate outside of protected areas.