Eagles are stunning creatures, so proud and graceful. And Bonelli’s Eagle is certainly no exception. They are also extremely agile flyers and are one of the most aggressive eagles.
The Bonelli’s Eagle is a beautiful bird of prey, athletically proportioned, with dark wings and tail contrasting with its whitish body. Sadly, however, they may not be around for long and are already considered at risk from extinction.
The Bonelli’s eagle, Latin name Aquila fasciata, are fairly spread out across the world.
Europe-wise, the species breeds from Southern Europe, and has been spotted as far east as southeastern China and Thailand, and as far west as Portugal.
They are also known to be found in the Sahara Desert in Africa, and across the Indian Subcontinent to Indonesia.
But here, we’ll give you the low down and tell you everything you might want to know about them, before they disappear for good.
Appearance
Although they’re quite large for a bird of prey, The Bonelli’s eagle is of a rather medium size for an eagle. And interestingly, the typical size of these birds depends very much on where they originate from.
(We won’t bog you down with all the different values here)
On average, however, they have a length ranging between 55 and 74 cm, which is between 22 and 29 inches. Males can typically weigh anywhere between 1.94 kilograms and 2.24 kilograms, which is between 3.1 and 4.9 pounds.
Females on the other hand are bigger and heavier. They typically weigh between 2.1 and 3.03 kilograms, which is between 4.6 and 6.7 pounds.
The male wingspan will typically fall between 143 and 163 cm, which is between 4 foot 8 inches and 5 foot 4 inches.
The female’s wingspan on the other hand will typically fall between 156 and 180 cm, in other words, between 5 foot 1 inch and 5 foot 11 inches.
In terms of color, the Bonelli’s Eagle adults are dark brown above, with a blackish median band, a mostly dark underwing, with white streaked underparts, a tail with a dark band at the end, and they have a conspicuous white patch in the center of their back.
Male Vs Female
Like most birds of prey, the Bonelli’s eagle shows reverse sexual dimorphism, which basically means that the female tends to be larger than the male. Ten percent larger on average, in fact.
(If you’ve been paying attention so far, you may have realized this already. The size and weights of the Bonelli’s eagle were described in the section on appearance.)
And another way to distinguish between male and female Bonelli’s eagles in their appearance is that the female has more heavily streaked underparts, while the male underparts are paler than those of the female.
Are They Aggressive?
The Bonelli eagle is a fierce and deadly hunter. Certainly one of the most aggressive of eagles, and are extremely territorial, very seldom found in the company of others, aside from their mate or family members.
Protection of their nests during breeding season is quite a spectacle. The male will pursue any creature who comes too close to the nest, and will even inflict injuries on larger birds such as vultures.
Going after prey sees even more determination and ferociousness. They will often fly down prey over considerably long distances.
What Adaptations Do They Have?
As we made reference to in the section on appearance, the size and wingspan of a Bonelli’s eagle differs according to where it lives, which is believed to be an adaptation to different habitats and environments.
Breeding / Reproduction Behavior
The Bonelli’s eagle is typically ready to breed within 3 years of their birth.
The breeding season of the Bonelli’s eagle differs according to where the bird is based. In Western areas, it starts between late January and early February and goes on to July.
Whereas on the Indian subcontinent it starts in November and goes on through to August or September.
Bonelli eagles sometimes live solitarily and sometimes in pairs. But when they do mate, they mate for life. And the pair will remain in each other’s company well beyond the end of the breeding season.
In order to signal interest in a mate, they perform an aerial display, which involves calling, high circling (singly or mutually) and sky dancing.
This sky dancing involves one or both of the pair diving or plunging headlong from a great height before rising again, and repeating this between 5 and 10 times.
The breeding success of Bonelli’s eagles may vary considerably. When it works, however, incubation is carried out by the female of the species, but the male will stay around to capture food for them both.
It is usually two eggs that are produced, and the incubation period lasts between 37 and 41 days in Europe, whereas on the Indian subcontinent this is slightly longer at between 40 and 45 days.
Their Calls / Sounds
The Bonelli’s eagle is not a particularly vocal bird and is largely silent when not in the breeding season. And even when trying to attract a mate, their calls are infrequent.
Their mating call can come from either sex, and consists of a loud, shrill noise, much like a far-carrying scream.
They can also make a fluted low-pitch sound, or a repeated sound in alarm. They can also make baking, gurgling and grunting sounds.
What Do They Eat? (Diet)
The largest part of a Bonelli’s eagle’s diet is made up of hares, rabbits, game birds such as partridges, crows, ducks and pigeons, and other large birds such as herons and storks.
But they have also been known to eat other species, too, such as rats, squirrels, foxes, and hedgehogs. During the summer, lizards are also fed on. And they take the majority of their prey alive.
Where Do They Live? (Habitat)
The Bonelli’s eagle like to spend their time in areas that present a balance between being wooded and being open, such as forest edges. They don’t like areas that are too densely forested, or too open. They also like hilly areas.
Bonelli’s eagles are fairly spread out across the world.
Europe-wise, the species breeds from Southern Europe, and has been spotted as far east as southeastern China and Thailand, and as far west as Portugal, They are also known to be found in the Sahara Desert in Africa, and across the Indian Subcontinent to Indonesia.
What Are Their Nesting Habits?
Bonelli eagles make very large nests with branches and sticks, averaging to 1.8 meters across, which is 5.9 feet, and 60 cm deep, which is 24 inches.
And the nest is often designed to completely obscure the sitting female from view. They are also often known to build nests on cliff edges, more so than on trees.
A female will typically produce two eggs on breeding, and will remain at the nest to incubate them. Meanwhile, the male bird will capture any food that is required.
It takes approximately one month for the Bonelli eagle to construct their nest, and they have been known to use the same nest in successive years.
How Long Do They Live? (Lifespan)
Bonelli’s eagles have a lifespan of approximately 15 to 20 years, which is relatively short when compared with other eagles.
What Predators Do They Have?
To be honest, the only main predator of Bonelli’s eagles are humans. It is humans that cause their habitat loss and their electrocution on pylons. Moreover, some people have been known to deliberately poison and illegally trap these creatures.
What Are Their Feathers Like?
Bonelli’s eagles have predominantly brown feathers with pale margins, which are especially broad on the median wing coverts.
Their color will depend somewhat on their state of molt, and there are regional variances on the color.
The male wingspan will typically fall between 143 and 163 cm, which is between 4 foot 8 inches and 5 foot 4 inches.
The female’s wingspan on the other hand will typically fall between 156 and 180 cm, in other words, between 5 foot 1 inch and 5 foot 11 inches.
What Does Their Poop Look Like?
Bonelli’s eagles excrete their urine and their feces together, so their poop is very liquid, despite there being so many solids in their diet.
Do They Migrate?
Bonelli’s eagles are largely residential throughout their lifespan, and are often considered non-migratory. However,some juvenile Bonelli’s eagles have been spotted at migration sites in the winter.
Conservation Status
The current conservation status of the Bonelli’s eagle is officially listed as being under extreme danger of extinction.
According to BirdLife International, the global population of Bonelli’s eagles is estimated to be at around 10,000.
Fun Facts
These eagles were named after the famous Italian ornithologist Franco Andrea Bonelli
Bonelli’s eagles have exceptionally long and well feathered legs
Bonelli’s eagles, when they do mate, mate for life
Bonelli’s eagles sometimes like to hunt in pairs
Bonelli’s eagles often make their nests high up on a cliff
