How The Peregrine Fund is Helping
Though The Peregrine Fund doesn't work directly with Bonelli's Eagles, our efforts in scientific research, habitat conservation, education, and community development help conserve birds of prey around the world. We also supply literature to researchers from our avian research library, which helps scientists around the world gather and share important information on raptor conservation.
Where They Live
This species has a wide geographic range. It is found in parts of southern Europe, northern and eastern Africa, the Middle East, India and other parts of Asia. Given the fact that it is distributed across such a large range, it stands to reason that it might be adaptable to using different habitat types, depending on the region of the world it lives in. However, in general this species can be found in mountainous areas up to 3,000 m, or hills, and forested or wooded plains. It hangs around cliffs, crags, and gorges. It is even sometimes found in eucalyptus plantations and native Cork Oak forests in parts of its range.
What They Do
These medium-sized eagles are diurnal raptors and they don't migrate. Though not as intricately marked as some other eagle species, the Bonelli's Eagle is still quite beautiful. Its wings and back are mostly a mix of darker feathers, while its underparts are white, with some fine streaking. Its long legs are completely covered with white feathers, making it appear as if it were wearing leg-warmers. Its feet are yellow as are its eyes and cere.
The Bonelli's Eagle is generally solitary throughout most of the year, meaning it spends most of its time hunting, soaring, or perching on its own. During this time it is also quite silent - this means researchers rarely hear these birds vocalizing. During breeding season, however, this does change. When mating season starts, the male and female eagles will begin to spend more time together and vocal communication plays a big part in their behavior. They use different calls - from shrill whistles to grunts and barks - for courtship, to alert each other to danger, to let each other know when they are nearby, and many other things.
Why They Need our Help
Bonelli's Eagle is classified as a species of "Least Concern" by BirdLife International. However, because of the species' wide distribution, it is clear that different populations are likely facing different threats, depending on where they live. For example, the European population, which is mostly in Spain, is regarded as Endangered. That is because this population is quite small and researchers have noted that is is also in decline. There, this eagle is often shot by hunters and pigeon fanciers and game keepers. Also, scientists still don't know enough about some of this species' populations - for example those found in parts of Asia and Africa - to really be able to understand what is happening and what the future might hold for this species.
Some of the main threats this species faces including shooting, collision with power lines and wind turbines, human-caused nest disturbance, and the loss of habitat to agriculture. Without good habitat, these eagles lose very important nesting sites as well as access to enough prey.
What They Eat
The Bonelli's Eagle's diet is composed mainly of rabbits, hares, and medium-sized birds, such as pigeons and partridges. It is also known to feed on rats, squirrels, foxes, bats, lizards, ducks, and various other species of birds, ranging from herons to doves and cuckoos, corvids, lapwings, sandpipers, woodpeckers, flycatchers, gulls, bustards, and more. Though not as common, it will also take larger prey such as storks, herons and buzzards!
While they are quite agile flyers, when on the hunt, Bonelli's Eagle captures most of its prey on the ground, though it will sometimes catch birds in flight. Sometimes, both the male and female of a breeding pair will work together to catch prey. Researchers studying this species in southern Europe observed that these eagles were most successful at catching prey when they had the element of surprise in their favor.
Nests, Eggs, and Young
Similar to many eagle species. the Bonelli's Eagle builds its nests out of large sticks and twigs. It may choose to build its nest on a cliff ledge, tree, or, even on electricity pylons. On occasion, it does sometimes nest close to human settlement. Because these eagles sometimes use their nests over and over in successive years, you can probably imagine that they can get to be quite big, measuring around 200 cm wide and 100 cm deep!
The female will lay between 1-2 eggs, which need to be incubated for between 37-40 days. After the nestlings hatch, they will grow quickly and remain in the nest until they are between 55-65 days old. Though the time it takes for young birds to fledge varies quite a bit, it is generally between 142-163 days. Once juveniles are ready to leave their parents' territory, they tend to disperse quite far.
It is believed that Bonelli's Eagle mates for life.
Bonelli's Eagle and the World Center for Birds of Prey
The World Center for Birds of Prey offers fun ways to learn about raptors. Interactive activities, tours, interesting videos and a children's room with activities from coloring sheets and quizzes to costumes and a touch table are available for the curious mind. We also have several different birds of prey on display year-round, including several eagle species! A visit to the World Center for Birds of Prey will reward you with a close-up look at several different eagle species from around the world including the beautiful Bateleur, the powerful Harpy Eagle and the majestic Bald Eagle. On display in an outdoor aviary, Stoffel, the Bateleur, delights visitors with his colorful plumage and entertaining behavior. Our experts and volunteers at the visitor center will help you learn more about the interesting traits, feeding habits, and reproductive behavior of this unusual eagle. Housed in our outdoor facilities, Sky the Bald Eagle greets visitors year-round from her chamber. When you walk the interpretive trail that looks out over the Boise valley in the winter, you may be able to spot a Bald Eagle soaring over the grasslands or perched in a tree or on a distant power pole. Grayson, the Harpy Eagle, will delight you with his gentle demeanor. We have a mounted eagle on display, real Harpy Eagle feathers you can touch, and a short video that chronicles the exciting journey of our biologists as they work to hatch young eagles, raise them, and ultimately release them into the dense forests of Panama. Fancy, our resident Ornate Hawk-eagle is an amazingly colorful bird of prey. Our knowledgeable staff and volunteers are on hand to answer any questions you may have about Bonelli's Eagle or other raptors
Global Raptor Information Network. 2021. Species account: Bonelli's Eagle Aquila fasciata. Downloaded from http://www.globalraptors.org on 18 Aug. 2021
Ontiveros, D. 1999. Selection of nest cliffs by Bonelli's Eagle (Hietus fasciatus) in southeastern Spain. Journal of Raptor Research, 33(2), 110-116.
Orta, J., G. M. Kirwan, D. A. Christie, P. F. D. Boesman, J. S. Marks, and E. F. J. Garcia 2020. Bonelli's Eagle (Aquila fasciata), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.boneag2.01