One of the most recognizable characteristics of birds is that they fly. Still, birds aren’t defined by an ability to fly, and there are a number of species worldwide that are ground-based. The most common reasons birds have evolved to be flightless are a lack of predators or the development of an alternative skill, such as swimming.
Discover the stories behind five iconic flightless birds and find out the unique characteristics that make each one special.
1. Penguins: Black and White Aquatic Birds
Penguins are a group of aquatic, flightless birds with distinctive black and white plumage. Most are found in the southern hemisphere, but some live at higher latitudes, including temperate regions such as the Galapagos islands. When it comes to iconic flightless birds, penguins top the list, as all 18 species cannot take to the air.
In simple terms, flippers don’t make good wings. Living in semi-aquatic environments, a penguin’s “wings” gradually made more efficient adjustments for swimming and diving. Water is much denser than air, so the wings became shorter and stiffer accordingly. These evolutions allowed the penguin to dive to lower depths in search of food, (the modern emperor penguin can hold its breath for up to 20 minutes to complement this skill).
But this aquatic ability came at a cost, and the penguin’s wings soon became inefficient for flight. Still, their feet are adapted for walking long distances, and penguins can also use them as rudders to help steer in the right direction as they glide through the water.
Their coloration is no accident either; the black backs help them blend in with the ocean’s hue as predators glance down from above. While the white belly blends in with the light striking the top of the water, which helps them camouflage from predators below.
2. Ostrich: African Flightless Birds
An ostrich is a flightless bird with a long neck and legs that lives on the African continent. As the world’s largest living bird, the ostrich can reach a height of 2.7m and weigh up to 159kg.
Most people believe that ostriches can’t fly because they are too big. This is true, but several other factors contributed to the ostrich becoming a ground-dwelling bird.
This large Avian’s ancestors were flying birds that would have flown through the skies when dinosaurs roamed the Earth. After the mass extinction of these fearsome reptiles, there was a lot of spare land for other animals to call their home. This meant that birds such as the ostrich began to adapt to life on Earth, growing bigger, stronger, and faster until they eventually forgot how to fly.
Still, the modern-day ostrich evolved with strong feet and powerful thighs, which allow it to run at speeds of up to 70km per hour, making it the fastest-running bird on the planet. A single stride of an ostrich can stretch five meters!
3. Kiwi: New Zealand’s Small Icon
The kiwi bird is a national symbol of New Zealand. It has been used in many ways, including on coins, stamps, and even as a mascot for sports teams. The kiwi bird is so iconic because it has been an essential part of the culture and economy of New Zealand for a long time.
The Kiwi is a flightless bird; because of this, it has evolved to have features that make it easier for them to survive on the ground. These features include having a strong sense of smell, long claws, and a large beak.
Kiwis cannot fly because they lack functioning wings; they possess tiny vestigial wings with a claw on the end, and their “feathers” are more hair-like in texture to suit their ground-based lifestyle. This means they rely on their strong sense of smell to help them find food and avoid predators.
According to the popular Māori legend, “How the Kiwi Lost its Wings,” this selfless little bird gave up its ability to fly to save the forests from a plague of bugs. In truth, the Kiwi is a member of the ratite family, many of whom lost the ability to fly because it was unnecessary. Flight requires a lot of energy, and before humans arrived, the Kiwi had no natural predators. For this reason, it was much easier for them to adapt to life on the land.
4. Kakapo: A Rare Flightless Bird Species
The Kakapo is a species of parrot found only in New Zealand. Like the Kiwi, this native bird adopted a ground-based lifestyle because it resided on an island with no natural predators. The Kakapo was once common across New Zealand, but after centuries of hunting and habitat destruction, it became extinct on the mainland. Today there are just 252 Kakapos left in the wild.
This green-colored bird is both the heaviest parrot in the world and the only flightless parrot. Its feathers are much softer than the average bird’s because they don’t require the strength and stiffness needed for flight. The Kakapo uses its wings for balance and support rather than flight, and they possess strong legs, which allow them to hike and climb extremely well.
Their wings have some functionality; for example, the Kakapo can climb to the top of a tree and then use the wings to act as a parachute down to the ground. And these birds are incredibly friendly. Many Maori and European settlers kept these birds as pets, and even wild Kakapos will approach and climb on people. As an endangered bird species, each one has a name and is extensively monitored.
5. Cassowary
The cassowary is a curious avian with the title of the world’s second-largest bird. There are three species of cassowary, the most common of which is the Southern Cassowary, one of many animals unique to Australia.
These unique birds are one of the closest living relatives to the dinosaurs, which you’ll realize when you look at one. They possess a prehistoric, bone-looking “cap” on their head known as a casque. No one is entirely sure what the purpose of the casque is, but scientists have a few theories.
One theory is that the casque could act as an antenna to pick up the vibrations of other cassowaries nearby. Another idea is that the casque could serve as a shock absorber as the cassowary headbutts its way through dense forest areas.
You should never approach a cassowary as they’re one of the only birds documented to have killed at least one human. Still, left to their own devices, they benefit the environment. These frugivores eat fruit that has fallen to the ground, then act as “natural gardeners” who disperse the seeds of these fruits and plants via their poop.
