A member of the sub-family of booted eagles due to its feather covered legs and named after the famous Italian ornithologist Franco Andrea Bonelli, the species is considered endangered across Europe but secure elsewhere within its range.
The Bonelli’s eagle is a medium sized eagle with elongated legs, large yellow feet and strong black talons. Adult males are predominantly dark brown above with a white mantle patch below the nape stretching towards the upper back and a long narrow grey tail tipped with black. The head is dark brown with a brown and white streaked neck and white throat. Breast and underbody are white streaked with dark brown with a white undertail tipped dark and brown underwings. There is a very dark black band along the edge of the underwing median coverts and a pale, almost white hue, to the leading edge of the underwing from the bastard wing extending to the body. Eyes are yellow and the hooked bill is grey to dark grey with a yellow cere from the base of the upper mandible to the nostrils. The feathered legs are mainly brown on the outer half and white with minimum streaking on the inside. Adult females tend to be up to 10% larger than males with heavier streaking to the underparts and darker overall. Juveniles have dark upperparts and are a light brown or tawny shade below, extending to the underwing coverts. Full adult plumage is reached at approximately four years of age.
Bonelli’s Eagle perched
Although mainly silent birds, during the breeding season they will become more vocal with a series of barks or yelps similar to ‘eeyou – eeyou’. Their alarm call is a repetitive ‘ki – ki – ki’.
Bonelli’s eagles survive on a diet of mainly medium sized birds similar to pigeons or partridges, occasionally caught in flight, or more usually mammals, including rabbits and squirrels. Sometimes hunting in pairs and following surprise ground attacks they have been known to take foxes.
A female Bonelli’s Eagle
Bonelli’s are generally non migratory, occupying their habitats year-round. Within Europe the greatest number are to be found in Spain including Mallorca, where the birds have been reintroduced. Breeding pairs are also to be found as far west as Portugal extending along the Mediterranean coast through southern France and the Balkans to Turkey. Whilst European numbers have been in decline for some time populations are strong in other parts of the range of the Bonelli’s eagle which extends through north west Africa, Senegal, Israel, Syria, the Arabian Peninsula, Saudi Arabia and the UAE, Afghanistan, Pakistan and Bangladesh, the Indian sub-continent, Thailand through to Indonesia and on to southern China.
Bonelli’s Eagle in flight
Mainly frequenting sunny, often arid regions, sightings are more common in mountainous and rocky areas or along cliffs or river gorges where they can be viewed gliding or soaring on flattened wings generally low to the ground searching for prey. Bonelli’s eagles are extremely territorial and whilst they will occupy areas of arable land and limited vegetation, they are unlikely to be found in heavily forested or highly overgrown regions which would afford admirable cover for their prey. They are seldom seen in company with others of their own species apart from its mate or family members.
Bonelli’s Eagle flying
Dependant upon location, breeding takes place between February to April in Europe and around the Mediterranean, January in north Africa and December to April across the Indian sub- continent. Nests are usually constructed out of large sticks and sited in caves, on steep ledges or occasionally in trees. One brood of normally two pale cream or white eggs with pale brown spotting is laid and incubated, predominantly by the female, for up to forty one days in Europe and up to 45 on the Indian sub-continent. Fledging starts around fifty six days of age up to a maximum of seventy days.
A pair of Bonelli’s Eagles
Juvenile Bonelli’s Eagle
The life expectancy of a Bonelli’s eagle is generally regarded as being up to a maximum of fifteen years.
Europe’s smallest eagle, the booted eagle, otherwise known as the Booted Hawk Eagle, prefers the warmer climes of southern Europe and south central Asia and whilst not threatened globally, its population within Europe is showing signs of decline.