Eagles are majestic and powerful birds that have fascinated humans for centuries. With their sharp talons and keen eyesight, they are incredible predators that can take down prey much larger than themselves.
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Despite their reputation for being large birds, there are actually many species of eagles that are much smaller than you might expect. In fact, the world’s smallest eagle, the South Nicobar Serpent eagle, is only the size of a house crow.
Weighing in at only 1 pound and measuring up to 17 inches in length, these tiny eagles may not seem like much, but they are no less impressive in their own way.
From the largest harpy eagles to the smallest South Nicobar Serpent eagles, these birds continue to captivate and inspire us with their incredible abilities.
Top 5 Smallest Eagle Species in the World
With a distribution that spans across the world, except for Antarctica, the eagle family comprises over 60 unique species. Below, we’ve compiled a list that showcases the top five smallest eagle species found on Earth:
- Great Nicobar Serpent Eagles
- Pygmy Eagles
- Booted Eagles
- Ayres’ Hawk Eagles
- Little Eagles
Great Nicobar Serpent Eagles
Scientific Name: Spilornis klossi
Length: 15 – 17 inches
Weight: 1 pound
Range: Nicobar Islands
The Nicobar serpent eagle, which is the smallest eagle species currently known, has an average length of 16 inches and weighs just a pound. Its distinguishing features include a dark brown back and wings, a tan breasts, greyish-white underbellies with a few tan streaks, and a brownish-black bushy crest. Its face is grey with a yellow mask that partially covers its beak, while its beak itself has a black hooked tip. If you examine the bird more closely, you will notice white stripes on its tail feathers. While they share similarities with the crested serpent eagles, the latter have mostly brown feathers and were once even considered a subspecies of the Nicobar serpent eagle.
Endemic to the primary forests of the Nicobar Archipelago, these tiny eagles tend to inhabit the canopies of these forests. Unfortunately, they are currently classified as near threatened due to habitat loss being the primary cause of their population decline. The Nicobar serpent eagles primarily feed on rodents, small birds, and reptiles.
Scientific Name: Hieraaetus weiskei
Length: 15 – 19 inches
Weight: 0.95 – 1.25 pounds
Range: New Guinea
The pygmy eagle is a small eagle that can be found in subtropical and tropical lowlands, as well as montane forests. They are also known as the New Guinea pygmy hawk-eagles, as they are indigenous to New Guinea.
At one point in time, pygmy eagles were considered the smallest eagle species, with a length of 15-19 inches and a wingspan of 44-50 inches. Their plumage comes in two morphs, one of which is lighter than the other. While most of their bodies are covered in brown feathers, their underparts primarily feature white feathers with brown streaks.
The New Guinea pygmy hawk has a stout body, a short, hooked beak, striped underwings, and a tail feather pattern that is visible during flight. Pygmy eagles have many similarities with other small eagle species that will be discussed in this article.
The weight of pygmy eagles varies depending on sex, with females weighing nearly 1.25 pounds and males weighing about 0.95 pounds. As carnivores, they primarily feed on smaller bird species and other vertebrates, much like many other eagle species.
Scientific Name: Hieraaetus pennatus
Length: 19 – 21 inches
Weight: 1.55 – 2.15 pounds
Range: Palearctic Region
The booted eagle is a species of eagle whose tarsi are covered in feathers, giving them their name. These small-sized eagles can have a wingspan of up to 3.9 feet and are usually between 19 to 21 inches in length. Females tend to be heavier than males and have an average weight of 2.1 pounds.
In addition to sexual dimorphism, booted eagles also display two colour morphs: light and dark. In the dark morph, their primary plumage colour is dark brown, with tan feathers and dark brown streaks covering their crown down to their nape. Their tarsi are sometimes covered in pale brown feathers, which contrasts with the rest of their blackish-brown bodies. They bear a striking resemblance to black kites and are less common than their lighter counterparts.
In the lighter morph, their underparts are covered in white feathers, and their flight feathers are dark brown with a few white streaks visible during flight. Their heads and the rest of their bodies are covered in white plumage with rufous-brown streaks and light brown feathers. Both colour morphs have yellow feet and bills that gradually change colour from yellow cere to grey to black tip.
The booted eagle is migratory and feeds primarily on medium-sized birds such as jays and pigeons, as well as other vertebrates and even insects at times. They tend to favour open lands and mountainous forests as their habitats.
Ayres’s Hawk Eagles
Scientific Name: Hieraaetus ayresii
Length: 18 – 22 inches
Weight: 1.35 – 1.58 pounds
Range: Sub-Saharan Africa
Ayres’ hawk eagles are a type of stocky raptor bird commonly found in many African countries south of the Saharan desert, making them one of the more widespread eagle species. They have an average length of 18-22 inches and a wingspan of up to nearly five feet, with females weighing slightly more than males. Ayres’ hawk eagles are monogamous and migratory birds that prefer habitats like woodlands, shrublands, savannas, and forests.
These birds of prey have a unique feather pattern, featuring mainly white and brownish-black plumage. Their slightly ruffled crests, upper bodies, and underparts are often covered in light feathers with thick streaks of brownish-black feathers. Additionally, their white and tan underwings are striped with brown bars.
Ayres’ hawk eagles, like some other small eagle species, primarily feed on birds, but they may also hunt tree-dwelling bats and rodents on occasion. The Ayres’ hawk eagle is closely related to other small eagle species such as the pygmy eagle, booted eagle, and little eagle.
Scientific Name: Hieraaetus morphnoides
Length: 17 – 22 inches
Weight: 0.97 – 1.8 pounds
Range: Australia and New Guinea
Little eagles are a small species of eagle that are indigenous to Australia, measuring an average of 17 to 22 inches in length and weighing up to 1.8 pounds. Females of this species are found to be almost twice the weight of male eagles. They come in two body forms, namely the light and dark forms, with the lighter ones being more abundant.
The little eagles have brownish-black plumage on their upper bodies and underparts, while their underwings and feathers are predominantly white with rufous-brown streaks. The darker form of this bird is identical, except their bodies are covered in primarily rufous brown and dark brown feathers with white or black streaks instead. They have feathered tarsi and pale feet with black talons.
They are widespread birds and are found in most of Australia’s mainland, preferring woodlands and open forests. However, their population is in decline due to the destruction of their habitat caused by human settlements.
Little eagles are opportunistic feeders and will hunt various animals, including small mammals, reptiles, birds, fish, and carrion.
Eagles are truly fascinating birds, impressive with the diverse characteristics that differentiate them from one another. From their diet and habitat preference to their colour and size, eagles are versatile raptors that capture our attention.
While most people know that eagles are powerful and fierce hunters, not many are aware that some species are actually quite small. In fact, the world’s smallest eagles are the great Nicobar serpent eagles, but that’s not all. Other species, such as pygmy eagles, booted eagles, Ayres’ hawk eagles, and little eagles, also belong to this category. These petite raptors’ size may surprise us, but they still demonstrate the skill and abilities of their larger cousins.
Growing up enjoying the beauty of my village, a good passion for nature developed in me from childhood. Following my passion for the natural world, I have chosen zoology for my graduation, during my undergraduate degree, I participated in many nature trails, bird watching, rescues, training for wildlife conservation, workshop, and seminars on biodiversity. I have a keen interest in invertebrate biology, herpetology, and ornithology. Primary interests include studies on taxonomy, ecology, habitat and behavior.