The martial eagle (Polemaetus bellicosus) is the largest species of eagle in Africa and the fifth heaviest in the world based on average weight. It reaches a length of 78-96 cm (31-38 in) and a weight of 3-6.2 kg (6.6-13.7 lb). Wingspan can be as large as 260 cm (8 ft 6 in). Adult birds have dark brown upperparts, head, and upper chest, white underparts with dark spots, and deep yellow eyes. Underwing coverts are dark brown, and flight feathers are pale with dark lines. Females are generally larger and more spotted than males. Immature birds are paler in appearance, often with white head and chest. It takes seven years for a martial eagle to reach adult plumage.
The martial eagle prefers more open habitats than the forest-dwelling crowned eagle, and the two species seldom compete directly. Martial eagles are often found in open woodlands, savannah, and thorny shrub-landscapes. Large trees are required for nesting purposes. Prey is usually spotted in flight, often from quite far away due to their exceptional vision, and attacked through a dive and swoop. Smaller prey are killed on impact, while larger prey are killed through strangulation. Diet is varied and changes from area to area, but mostly consist of large birds such as fowl, bustards, and waterfowl, large reptiles such as monitors and snakes, and mammals up to the size of impala calves.
The martial eagle is a monogamous solitary breeder with partner-bonds often lasting several breeding seasons. Breeding season varies within its range. The nests are huge platforms made of twigs and branches often set in forks high up in tall trees, normally between 6 to 20 meters (20-66 ft) up. The female builds the nest over 2-3 weeks. As the nest is reused over several breeding seasons, it will increase in size sometimes reaching depths of over 2 m (6.6 ft). Nests have sometimes been observed on pylons.
The female generally lays only one egg which is incubated for 48-53 days. The male hunts and provides food for the first 2-3 weeks after hatching as she broods, before she starts assisting. After 90-109 days the chick normally leaves the nest, but will be dependent on both parents for another 6-12 months, making martial eagles able to breed only every two years.
The martial eagle has seen a great decline in numbers due to human activities. In many areas it is persecuted by farmers in the belief that it poses a threat to livestock, which is only occasionally killed by martial eagles. Martial eagles generally prefer remote areas away from human habitation, so human population growth and loss of habitat are also a large contributors to its decline. It has always been an uncommon species throughout most of its range, likely due to large home ranges, and it is now almost exclusively found within protected areas. It is listed as vulnerable on the IUCN Red List.
If you want to help in the conservation of the martial eagle you can support the Percy FitzPatrick Institute of African Ornithology: