The Martial eagle is the largest eagle of Africa. 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 eyes of mature Martial eagles are rich yellow, while the cere and large feet pale greenish and the talons black. Juveniles are conspicuously distinct in plumage with a pearly gray color above with considerable white edging, as well as a speckled grey effect on the 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. The eyes of the juveniles are dark brown.
Martial eagles are found in most of sub-Saharan Africa. They prefer to live in open woods and woodland edges, wooded savannah and thornbush habitats. These eagles also avoid closed-canopy forests and hyper-arid desert. In southern Africa, they have adapted to more open habitats than elsewhere in their range, such as semi-desert and open savanna with scattered trees, and wooded hillocks. In the desert areas of Namibia, they utilize ephemeral rivers. Martial eagles seem to prefer desolate or protected areas.
Martial eagles are diurnal, often spending a large portion of the day on the wing, and often at a great height. When not breeding, both mature eagles from a breeding pair may be found roosting on their own in some tree up to several miles from their nesting haunt, probably hunting for several days in one area, and then moving on to another area. Martial eagles usually hunt in a long, shallow stoop, however, when the quarry is seen in a more enclosed space, they parachute down at a relatively steeper angle. Prey may often be spotted from 3 to 5 km (1.9 to 3.1 mi) away with a record of about 6 km (3.7 mi). On occasion, Martial eagles 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. Martial eagles tend to be very solitary and do not tolerate other eagles in the area outside of the pair during the breeding season. In general, these birds are shy and try to avoid humans, but may be seen passing overpopulated country at times. These powerful hunters are relatively quiet birds. When near the nest or excited, they produce “hlueee-oh” and during display birds utter series of “klee-klee-klee-kloeee-kloeee-kulee”.
Martial eagles are carnivorous opportunistic predators that prey on mammals, birds, and reptiles. They hunt small antelopes, some monkeys, young domestic goats and lambs, water birds such as herons, storks, and geese. At other times, these eagles may prey upon a wide range of potentially dangerous prey, such as monitor lizards, venomous snakes, jackals, and medium-sized wild cats.
Martial eagles form monogamous pairs, which stay together for life. The birds don’t have a spectacular display flight. Their display often consists of the adult male or both members of a pair circling and calling over their home range area. During mutual circling, the adult female may turn and present talons. Martial eagles may breed in various months in the different parts of their range. In Senegal, the mating season takes place in November-April, January to June in Sudan, August to July in northeast Africa and almost any month in east Africa and southern Africa, though mostly in April-November. Pairs build their nests in large trees and usually place them in the main fork of the tree at 6-20 m (20-66 ft) off the ground. Females usually lay one egg (rarely two) every two years. The egg is incubated for 45 to 53 days mainly by the female. The newly hatched chicks are usually quite weak and feeble, becoming more active only after they are 20 days old. The chicks usually first feed themselves at 9 to 11 weeks old and fledge at 96 to 109 days. They may remain in the care of their parents for a further 6 to 12 months and will reach reproductive maturity at 4 to 5 years of age.
The main threats to Martial eagles include hunting and habitat loss. The birds are killed by farmers because they hunt some domestic animals. Viewed by farmers as a threat to livestock, eagles are often poisoned and shot. Other threats come from powerline collisions and habitat destruction. The eagle’s low reproductive rate is also a problem for its long-term survival.
According to the Africa Geographic resource, the total population size of the Martial eagle is approximately 30,000 individuals. According to the IUCN Red List, the population of this species in South Africa, Lesotho and Swaziland is around 800 pairs and the population in Namibia includes less than 350 pairs. Currently, Martial eagles are classified as Vulnerable (VU) on the IUCN Red List and their numbers today are decreasing.
Martial eagles are apex predators and are at the top of the avian food chain in their environment. Due to their opportunistic diet, these birds control the population of their prey species.