The Wahlberg’s eagle is a majestic and unique raptor native to Sub-Saharan Africa, but as it’s quite a bit smaller than standard brown eagles, the species often flies under our radar (pun definitely intended).
So, let’s take a closer look and give this beautiful bird the attention it deserves.
Appearance
As we’ve already touched upon, the Wahlberg’s eagle is quite a small variant, with dark to chocolate-brown upper plumage that grows ever so slightly lighter towards the upper wing.
The flight feathers of their underwings are usually gray-brown and feature dark yet narrow brown barring.
Compared to larger brown eagles, they have a fairly slight head, and they can weigh anything between 437-1400 grams (0.96-3.08lbs).
They tend to measure 53-71cm (20-27.9”) in length and boast a fairly impressive wingspan of 130-146cm (51.18-57.48”).
They have yellow legs with black talons, brown eyes, a pointed crest, a short black bill with a yellow cere, and a faintly barred gray undertail. Their rounded nostrils separate them from tawny and steppe eagles.
Often mistaken for lesser spotted eagles, the two species can be distinguished from one another by the reach of their gape.
In Wahlberg eagles, the top of the bill reaches the middle of their eyes, while the top of a lesser spotted eagle’s bill terminates towards the back of its eyes.
When in flight, the straight edges of their wings (which are held flat) and tail resemble a crucifix.
Their tail feathers are usually held in a narrow formation, rarely exceeding the width of their slim bodies; however, to gain lift in thermals, they will occasionally fan their tail.
There have also been a few isolated reports of a lighter morph within the species; with pale brown topsides; creamy-white heads and necks with dark streaks, white-edged feathers, and near-white undertails.
The plumage of juvenile Wahlberg’s eagles mirrors the morph of their parents, albeit with slightly paler back feathers and upper-wing covert fringes.
Male Vs Female
It can be incredibly difficult to differentiate between male and female Wahlberg’s eagles as they have more or less the same coloring and features, but there are is one giveaway to mention…their size.
The Female Wahlberg’s eagle can be significantly larger than the male. The difference in body mass between the two sexes is so stark that even the smallest female specimen will weigh almost as much as the largest male.
Unfortunately, as there’s a possible overlap of 175 grams (0.385lbs) between the males and females of the species, size and body mass aren’t always reliable ways of telling the sexes apart.
Are They Aggressive?
Wahlberg’s eagles can be incredibly aggressive towards other animals, often engaging in conflicts mid-flight; however, as long as we stay out of their territory, they’re unlikely to show hostility towards humans or other large mammals.
What Adaptations Do They Have?
These unique eagles have mostly humdrum adaptations such as long claws for hunting prey and grasping branches, but there is one particularly interesting behavioral trait to mention.
The breeding period of the Wahlberg’s eagle is decidedly short in comparison to similar birds of prey. It’s thought that this is a migratory adaptation, allowing them to travel alongside their young to more temperate climates when the cold seasons arrive.
Breeding/Reproduction Behavior
The breeding season of Wahlberg’s eagles differs depending on the range, but for most, it takes place during the wet season between September and February.
For the minority residing in eastern Africa, it’s more likely to occur between July and November.
A female eagle’s clutch normally only consists of a single white egg with reddish-brown markings. She will lay two on occasion, but only one infant will survive, for the weaker will be killed as a result of Cainism (siblings killing siblings).
The incubation period usually lasts for 43-46 days, and consists primarily of the female warming, and protecting the egg, while the male hunts for food to feed them both.
That said, the male will take over parental duties once in a while to give the mother some respite.
After a 62-80 day fledgling period, the family of eagles is ready to migrate.
Their Calls/Sounds
While these birds tend to be quite quiet throughout the year, they do become very vocal during the breeding season. Their display call is a “quieee-aow” sound.
It’s used both when they’re in flight and perched, and it’s thought to sound quite sorrowful. They also use a yelped “Kyip-kyip-kyip” sound as a greeting when they’re approaching the nest.
Outside of the breeding season, they’re known to let out a whistled “Kleeah-kleeah-kleeah” sound while perched on a branch.
What Do They Eat? (Diet)
Wahlberg’s eagles aren’t too picky when it comes to food. They’ll snack on just about anything as long as it’s smaller than them.
As birds of prey, they’re partial to nipping other birds such as guinea fowls and larks out of the sky, but they’re just as happy descending upon small mammals such as hares, mongooses, squirrels, rats, and mice.
But they don’t care if their food is feathered, fluffy, or otherwise, as snakes, lizards, and frogs are also on the menu. As are insects such as termites and ants.
In fact, studies show that at 40.2%, reptiles make up the majority of their diet, followed closely by birds (31.5%), and then small mammals (28.3%).
When hunting insects, these eagles will perch on the ground and pick at them. If they’re hunting for birds, they’ll perch on a high branch, wait for something to fly by, then shoot after them, catching them unawares.
To snag themselves a small mammal for dinner, they tend to glide around 25 meters above ground until they find a target.
Then, they’ll begin a steady descent, hanging over the prey until they reach a suitable height to swoop down at full speed and claim their victim.
They’ve also been observed perching ominously at the periphery of bushfires, waiting for fleeing prey to emerge from the chaos.
Where Do They Live? (Habitat)
Wahlberg’s eagles enjoy a fairly wide range spanning south Mauritania and Senegambia, Sudan, Eritrea, Ethiopia, Botswana, north and east South Africa, Angola, and Namibia.
They can be found in the woodlands of Sub-Saharan Africa, but they tend to distance themselves from dense forestry, as well as mountainous and open, arid areas. They much prefer an even spread of wood and grasslands.
What Are Their Nesting Habits?
Their ideal nesting sites are situated near dry river courses in valleys. The male and female collect materials and craft the small nest together out of twigs before lining it with green leaves.
They’ll typically station their nest between 5-22 meters high, below the canopy of acacia, eucalyptus, or baobab trees.
Wahlberg’s eagles are almost entirely monogamous creatures that form incredibly strong bonds with their mates. As such, if their initial nest survives, it’ll be used by the same pair of eagles in successive years.
How Long Do They Live? (Lifespan)
Wahlberg’s eagles tend to live for around 12 years, which isn’t very long when compared to the lifespan of other eagles. Take the crowned eagle, for instance.
It has a lifespan of 14 years, and let’s not forget that mighty bald eagle, which can live to the ripe old age of 20.
What Predators Do They Have?
The Wahlberg’s eagle’s only real threat comes in the form of larger birds of prey, such as the giant eagle owl. Some larger and venomous snakes probably pose a threat too, but the two species may never get close enough for the snake to strike.
What Are Their Feathers Like?
Their top-side feathers are usually light to dark brown, while their undersides tend to have a gray-brown hue and dark barring. They have pale primary feather bases, and dark flight feathers.
What Does Their Poop Look Like?
The scat of Wahlberg’s eagles can take a couple of forms; it all depends on what they’ve been eating.
If their diet has been a little mammal or bird-heavy, their droppings will appear as tightly packed feathers and fluff with the odd skeletal fragment jutting out.
If they’ve been eating a lot of insects and reptiles, their droppings will resemble more closely the white-black scat of the average songbird.
Do They Migrate?
Wahlberg’s eagles do indeed migrate. They engage in both intra-African and trans-equatorial flight in order to escape the cold weather. The majority of the species overwinters in Sudan and Nigeria.
During a 10-month period, an adult female Wahlberg’s eagle was tracked over a total distance of 8816km, traveling through northern Cameroon, north-eastern Nigeria, Western Chad, Congo, and Zaire.
Conservation Status
The IUCN conservation status categorizes Wahlberg’s eagles under LC, an abbreviation of “Least Concern”, meaning their population is under no threat of extinction.
Fun Facts
Wahlberg’s eagles were named for the famed Swedish naturalist, Johan August Wahlberg.
They’ve been seen to perform beautiful, undulating sky dances.
There are several morphs of Wahlberg’s eagle, the rarest of which is the light variant.
The migration patterns of the Wahlberg’s eagle are based on rainfall patterns. They always seem to arrive during the wet season of their northern and southernmost ranges.
