The Booted Eagles (Hieraaetus pennatus and also classified as Aquila pennata) is a bird of prey with a wide population in the Palearctic and southern Asia.
Largely migratory, this medium-sized raptor migrates to the tropics of Africa and other regions of Asia during the winter months. A small group of the breeding population also head to southern-western Africa.
As with all eagles, the Booted eagle belongs to the Accipitridae family. A small eagle, this species of bird is most comparable to the common buzzard in its size. However, it is far more eagle-like in shape and appearance.
To understand just about everything there is to know about the Booted eagle, read on as we discuss its habitat, lifespan, nesting habits, and the different calls and sounds it makes.
Appearance
There are two quite distinct plumage forms with the Booted eagle. This buzzard-sized eagle has a long tail to accompany its slender build. It sports white patches at the base of its wings and they occur in pale and dark morphings.
Pale birds can sometimes be confused with the larger Egyptian vulture but the tail of the Egyptian species has a wedge shape. The pale birds have a mainly light grey color with a darker head and flight feathers.
The other plumage form has a mid-brown plumage accompanied by dark grey flight-feathers.
Male vs Female
Although small in stature, the females are larger than the males. Male Booted eagles grow to about 510 – 770 g (1.12 – 1.70 lbs) whereas females can weigh up to 840 – 1,025 g.
Their length is generally around 40 cm with a wingspan of 11 – 132 cm. The plumage of the sexes is very similar.
Are they aggressive?
The Booted eagle is not known as an aggressive bird of prey. Although territorial, especially when they have eggs and fledglings, these raptors tend to keep to themselves. But, when they hunt, they are aggressive, killing small mammals, birds, and reptiles.
What adaptions do they have?
Genetic research has found that this species of eagle is in the genus Aquila along with some, or all, of the other Hieraaetus species.
DNA research has also found that the Booted eagle forms a monophyletic clade with Ayres’ hawk-eagle, little eagle, Wahlberg’s eagle, and the pygmy eagle. Not a lot is known about their adaptions in the wild but more studies are currently underway to find out more about this fascinating species.
Breeding/reproduction behavior
It is still unclear what age a Booted eagle first becomes capable of breeding. However, studies conducted in 2012, 2014, and 2015 found that the birds started to breed during March.
During these three years, the incubation period ranged from 33 to 38 days whilst the frequency of the distribution of clutch sizes was 67.6% for 2 eggs, 27% for 1 egg, and 5.4% for 3 eggs. Very little variation in hatching occurred over the three years.
During their courtship, incredibly fast and wonderful stoops can be witnessed. Their nests are usually made on trees but rarely on cliffs and they usually use the nests of other species of raptors or crows.
In general, 2 eggs are usually laid but, as found in that three-year study, sometimes 1 or 3 eggs are laid. The incubation time tends to be around 36-40 days and the young generally remain in their nests for another 50 to 55 days.
As with other raptors, the young stay dependent on their parents after fledging. However, this period is rather short for Booted eagles at approximately two weeks.
Their calls/sounds
Although quite quiet most of the time, during the breeding season, the Booted eagle becomes extremely vocal.
Nevertheless, you will usually hear quite a soft, wader-like series of sounds along the lines of “kli-kli-kli-kli-kli-kli.” This can be quite shrill at times, however. Try and reproduce the sound yourself!
What do they eat? (Diet)
The Booted eagle usually hunts small mammals, reptiles, and birds. Most of their hunting is done from the ground but they can swoop down after waiting for their prey to appear.
While larger insects like locusts form a portion of their diets, it’s different varieties of birds and mammals that make up the majority of their food. Some of these mammals are even up to the size of a rabbit.
They frequently locate their prey while being perched nearby which they can catch from a super-fast, almost vertical swoop from above.
Where do they live? (Habitat)
These birds of prey breed in southern Europe, across North Africa, and in many areas of Asia. They are also known to breed in western Africa and Namibia.
The northern populations of the Booted eagle are migratory. They spend the months from November to February in Sub-Saharan Africa and South Asia. the smaller southern African populations are sedentary and remain.
Their habitat is usually in wooded, often hilly areas of the countryside alongside some open spaces. They breed in rocky, broken terrain but migrants tend to use almost any kind of habitat other than a dense, thick forested area.
What are their nesting habits?
The Booted eagle usually lays 1 to 2 eggs in a nest (but this varies as we discussed above). The nests are built from sticks but are typically lined with green, fresh leaves in a tree or sometimes on a crag.
They do not always build their own nests, though. Booted eagles are notorious for taking over other bird’s nests. Generally, these are larger species such as a grey heron or a black kite. But, they usually wait until the nest is unused.
Females incubate the egg for approximately 45 days while she is fed by the male. After hatching takes place, the female guards the nest and her young while the male forages for food and provides it for his family. After 70 to 75 days, the chick will fledge.
How long do they live? (Lifespan)
When in captivity, the Booted eagle has an average lifespan of around 12 to 15 years. It is currently unknown what the average lifespan of these eagles is in the wild but it is estimated to be a little shorter than those kept in captivity.
There have actually been examples of Booted eagles living over 20 years of age in some cases.
What predators do they have?
Due to their relatively small size, Booted eagles are prey for some other larger birds.
Larger eagles are the main predators of these birds but, as with many wildlife species, humans are the main predator as encroaching human habitats and growing populations destroy their own habitats and source for food.
What are their feathers like?
The two-color morphs of the Booted eagle are quite distinct but mainly confined to its underparts. The pale form tends to be the most common, however.
The upper parts of both forms of the bird, including the upper wing and tail, are similar.
They have dark grey flight feathers, both primaries, and secondaries, with lighter brownish coverts that fade into a paler (almost white) color at the tips. These form a pale band that goes diagonally.
The rump of the eagle has a white crescent and it has two distinct bright white spots on its shoulder right next to the neck.
The upper tail coverts also sport a pale brown hue while the trailing edges of both of their wings are nearly all white, appearing almost translucent. This becomes particularly visible as they fly.
The pale morph has white underparts. Their underwing coverts have white feathered legs and a grey-brown head. The underwing flight feathers are predominately a dark grey and brown color.
Their fan-shaped undertail feathers tend to be white alongside their coverts.
The dark form of the Booted eagle has a dull brown color across its underparts along with a pale patch that runs from the base of the fingered wingtips. These stretch to the edge of their primaries where they eventually meet up with the secondary flight feathers.
What does their poop look like?
In Booted eagles, as with most birds, the feces and urine are excreted together. This produces a white poop that is synonymous with the majority of birds. The reason it’s white is due to the uric acid that is released with the feces.
Do they migrate?
Booted eagles breed in southern Europe, especially along the Mediterranean coastline such as Gibraltar and the Balearic island. They are also found throughout Greece, Israel, Iran, the Middle East, across the Himalayas, Morocco, Algeria, Tunisia, and South Africa.
During the winter months, most of the species migrate into Sub-Saharan Africa, southern Asia, as well as the Indian subcontinent.
Conservation status
This species has a very large range. Therefore, they are not considered vulnerable at this stage. However, their populations are dwindling but this decrease is not considered sufficiently rapid enough to approach the worrying level of vulnerability.
Fun facts
As well as the little eagle, the Booted eagle is considered to be one of the closest relatives to the now extinct Haast’s eagle of New Zealand. A true passage back in time.
