African crowned eagle, Crowned hawk-eagle , Crowned hawk-eagle
The crowned eagle, also known as the African crowned eagle or the crowned hawk-eagle (Stephanoaetus coronatus ), is a large bird of prey found in sub-Saharan Africa; in Southern Africa it is restricted to eastern areas. Its preferred habitats are principally riparian woodlands and various forests. The crowned eagle is the only extant member of the genus Stephanoaetus. A second species, the Malagasy crowned eagle (Stephanoaetus mahery ) became extinct after humans settled on Madagascar.
At least 90 percent of the diet is mammalian; the usual prey taken by populations shows pronounced regional differences. Throughout its range the principal prey items are small ungulates (such as duikers, chevrotains), rock hyrax and small primates such as monkeys. Birds and large lizards are barely taken.
Although the crowned eagle's long tail imparts an overall length up to 90 cm (35 in), it is somewhat less massive and has a considerably shorter wingspan than Africa's largest eagle, the martial eagle (Polemaetus bellicosus ). It is nevertheless considered Africa's most powerful eagle when measured in terms of the weight of its prey items. It often preys on mammals such as bushbuck (Tragelaphus scriptus ), exceptionally weighing up to 30 kg (66 lb) albeit usually much less. The crowned eagle possesses unusually large talons and strong legs, and may kill by crushing the skull. The eagle is also ferocious; some records from beneath a nest show the remains of a large, male Sooty mangabey weighing 11 kg (24 lb).
Due to their ecological similarities, the crowned eagle is considered to be the African counterpart of the harpy eagle (Harpia harpyja ). Thanks to its bold and highly conspicuous behavior, it is exceptionally well-studied for a large, forest-dwelling eagle. Due to a relatively high level of habitat adaptability, it was until recently considered to be faring well by the standards of large, forest-dependent raptors. However, today it is generally thought that it is decreasing far more than was previously perceived due to the almost epidemic destruction of native tropical African forest. It is now listed by the IUCN as Near Threatened.
The Crowned eagle is the most powerful raptor of sub-Saharan Africa. The adult bird is quite strikingly plumaged. Its crown is dark to rufous-tinged brown with a prominent, oft-raised black-tipped double crest, which can give the head a somewhat triangular appearance. The upperparts are a blackish brown-grey color, with a variable tinge of blue. The throat is brown while the belly and breast are white overlaid densely with blackish bars and blotches, variably marked with cream or rich buff-rufous coloration. The wing primaries (flight feathers) are white at the base, broadly tipped with black and crossed by two black bars. The tail is black with brownish-grey bands. The underwing coverts have a bold chestnut coloration, spotted lightly with black. The adult Crowned eagle has eyes that can range from yellow to almost white. This beautiful hunter possesses unusually large talons and strong legs and may kill by crushing the skull.
Crowned eagles are found only in Africa. In East Africa, their range extends from central Ethiopia to Uganda, forested parts of Kenya and Tanzania to as far south as eastern South Africa, with a southern distribution limit around Knysna. In western and central Africa, Crowned eagles may be found from Senegal, The Gambia, Sierra Leone, and Cameroon, where they inhabit the Guinean forests, to the Democratic Republic of the Congo, where they live in the Congolian forests, and down south to as far Angola. Despite their large distribution there, Crowned eagle are now rare in many parts of West Africa. These raptors inhabit mainly dense woodlands, including those deep within the rainforest, but will sometimes also be found in relict patches, wooded escarpments, riparian strips of Acacia, heavily wooded hillsides, and rocky outcrops throughout their range. Around stretches of East Africa, Crowned eagles usually live in wooded areas of rocky hills and narrow riverine strips, only rarely ranging into savanna surrounding the hills. In South Africa, they occur in both lowland and montane evergreen forest, dense woodland, and forested ravines and gorges in open savannas and thornveld.
Crowned eagles live in pairs. They are largely sedentary and usually inhabit a fixed territory throughout the year. Crowned eagles are considered nervous, constantly alert and on edge. However, their main hunting techniques require long periods of inactivity, spent sitting on a perch. Crowned eagles may hunt alone or in pairs and mainly kill early in the morning and in the evening prior to sundown. These beautiful hunters may locate a suitable hunting spot by listening (such as via the call of the noisy vervet monkey) or watching for prey activity, though may also use habitual hunting perches where they've previously had hunting successes. They often still-hunt, wherein they drop or stoop onto prey from a branch perch. Crowned eagles are highly vocal and have a noisy, undulating display flight. The male performs an elaborate rise-and-fall display over the forest canopy both during the breeding season and outside as a territorial proposition. Territorial displays consist of a series of steep dives and ascents, with a few wing-flaps at the top of each climb and descending circles and figures of eight. During descents, eagles can drop as much as 60 m (200 ft) at a time before circling back up. During this display, the male is noisy, uttering a shrill kewee-kewee-kewee while throwing his head back. The adult female may also perform independent display flights, uttering a lower kooee-kooee-kooee. Pairs also perform visually striking mutual displays, sometimes arising from the first type or when the pairs come together after a brief absence. While awaiting food at the nest, both the female and the young produce high kwee-kwee-kwee.
Crowned eagles are carnivores and most of their diet consists of mammals. They hunt mainly small ungulates (such as duikers, chevrotains), rock hyrax and small primates such as monkeys. Birds and large lizards are taken occasionally.
Crowned eagles are monogamous and mate for life. Pairs usually breed once every two years almost year-around, though egg-laying seems to peak from July to November. After engaging in the breeding display, the pair starts to build a massive nest in a fork of a large forest tree, usually 12-45 m (39-148 ft) above the ground. While the female fetches more nesting material, the male tends to be more active in nest construction. The female lays 1 or 2 eggs usually just white, though may sometimes be overlaid with sparse red-brown markings. Incubation lasts around 49 days done mainly by the female. The male brings food to the incubating female every 3 to 5 days. The young hatch, covered in down, and first feathers appear in 40 days. If two eggs are laid, the younger one dies by starvation after being outcompeted for food by the older one or even directly killed by its older sibling. After 40 days of age, the young is capable of feeding itself, though is often still fed. The young fledge at 90 to 115 days but remains in the care of its parents for another 11 months. It is estimated that most Crowned eagles reach breeding maturity at around five years old.
Today, the population of Crowned eagle is decreasing due to the almost epidemic destruction of the native tropical African forest. This species main habitat is rich, high-canopy forest, which is a major target of timber companies, agriculturists, palm oil and biofuel plantations and miners as well as slash and burns farmers. The Crowned eagle also suffers from persecution because of its size, reputation, and potential for taking small livestock; the birds are often shot, trapped or their nests are destroyed.
According to the IUCN Red List, the total Crowned eagle population size is around 5,000-50,000 mature individuals. Currently, this species is classified as Near Threatened (NT) on the IUCN Red List and its numbers today are decreasing.
Crowned eagles play an important role in the local ecosystem, controlling prey populations.
