Flightlessness is an evolutionary trait in which birds lose their ability to fly. The most well known flightless birds are penguins and ratites; a diverse group of birds with relatively large bodies and long-legs, including emu, rheas, and ostriches. Although much smaller, Kiwis are also classified as ratites.
The evolution of flightlessness started about 66 million years ago right after the Cretaceous–Paleogene extinction event, which resulted in the extinction of all non-avian dinosaurs.
The ratite ancestors that survived the mass extinction went through morphological changes best suited to protect their territories and fulfill dietary needs.
Apparently, different bird species have evolved to flightlessness independently. For example, species such as domestic duck have almost completely lost the ability to fly, but its ancestral species, the Mallard, have somehow retained that ability.
Below is a list of 12 flightless bird species that you should know.
A common ostrich in Ngorongoro, Tanzania | Image Courtesy: Nevit Dilmen
Originated From: Africa and Europe
Ostriches, native to the African continent, are recognized by their long, bare neck and legs. Unlike flying birds, ostriches lack keel; an extension of the breastbone, which is essential for making extended flights.
There are two extant ostrich species known to us; the common ostrich and the Somali ostrich. The common ostrich can be further categorized into three living subspecies. Their skin color ranges from dark grey to pinkish-grey.
Physically identical to the common ostrich, the Somali ostrich has blueish-grey neck and legs (male).
Species: Dromaius novaehollandiae
Emus are the second tallest and one of the heaviest birds on Earth. An average male emu can extend up to 148.5 cm in height and weigh between 31 and 37 kg. Like the ostrich, emus are soft feathered and have long legs, and neck.
They feature about 20 cm long wings or wing cords, which helps them stabilize while running at fast speeds. Emus have sharp claws and extremely strong legs. The portion of total body mass contributed by pelvic limb muscles is similar to that of flight muscles in birds that are capable of extended flying.
Emus are social as well as non-nocturnal animals; engaging in foraging and other activities only during day time. They are also capable of swimming.
A North Island brown kiwi
New Zealand is known for its rich flora and fauna. A number of the species located there are in fact endemic, i.e, they are only found on the island nation. One of them is New Zealand’s national bird, Kiwi.
Kiwi is the smallest ratite species on earth. Interestingly, however, studies have shown that Kiwis are genetically close to giant Malagasy elephant bird, an extinct flightless bird species. They have several distinct characteristics, most evident being the long beak with which the Kiwi track preys.
Though not visible, Kiwi’s also possess small wings, which are completely covered with their feathers.
Southern Cassowary | Scott Hamlin/Flickr
After ostrich and emu, cassowaries are the tallest and heaviest birds on the planet. At least four species of cassowaries are known, one of which is now extinct. All three species are native to New Guinea and its surrounding islands.
Cassowaries feature small wings with about half-a-dozen large asymmetrically shaped features. Two specific bones, which plays an important role in bird flight, namely coracoid and furcula, are almost completely gone. They do not possess tail feathers.
Cassowaries are perhaps the world’s most dangerous birds. In 2003, a study reveled out of nearly 220 attacks by these birds, 150 were against humans. Only two of those attacks proved out to be fatal.
A running rhea | Image Courtesy: Juan Eduardo Cristófaro
Rheas are flightless birds with physical attributes similar to that of ostriches. Found only in South America, Rheas can be classified into two (out of eight known, only two are living) subspecies; Greater rhea and Darwin’s rhea.
Both species exhibit slightly larger wings than other ratites.
7. Steamer Duck
Fuegian steamer duck at Cologne Zoo | Wikimedia Commons
The Steamer ducks of family Anatidae (water birds) got their name from a distinct sound they make while swimming. Along with feet, these birds use their wings to paddle through the water. There are four species of steamer ducks, all of which are native to the Falkland Islands, parts of Argentina and Chile.
The most widespread of all four steamer duck species is the flying steamer duck, which, unlike the other three, can fly for a short period of time. The Magellanic flightless steamer duck is one of the heaviest duck species in the world.
Steamer ducks are highly aggressive towards other waterbird species and are well capable of defending themselves against predatory species like Petrels.
6. Titicaca grebe
Titicaca grebe | Image Courtesy: Ryan O’Donnell
Scientific Name: R. microptera
Named after the lake Titicaca (located between Peru-Bolivia border), Titicaca grebe is a short-winged grebe, which is easily identified by vibrant color patterns on their upper body.
An adult Titicaca grebe can weigh up to 600 grams and extend to 45 cm in total length. Even though weak and unable to take flight, its wings play an important role while running and diving.
The species is classified as endangered, with a total population of just 1,600 individuals.
5. Flightless cormorant
A flightless cormorant | Image Courtesy: sharpphotography
Scientific Name: Phalacrocorax harrisi
Flightless cormorant, or Galapagos cormorant, is the only extant cormorant species that has evolved to become flightless. Physically, flightless cormorant is just like any other cormorant species; strong legs with webbed toes, but with much denser and softer feathers. However, it is possible to misidentify a flightless cormorant for a wild duck due to modest, but apparent similarities.
Only found in remote Galapagos Islands, the flightless cormorants lived under little or no threat from natural predators for a long time. The flight feathers, which traps air to keep birds afloat, would have made these cormorants less efficient divers. These factors have driven the species to lose the ability to fly over time.
4. King Penguin
King penguin chick | Image Courtesy: Liam Quinn/Flickr
Scientific Name: Aptenodytes patagonicus
King penguin is one of the two living species of the genus Aptenodytes, the other is Emperor penguin. The King penguin, bearing a close resemblance to Emperor penguins, have colored cheeks (lower jaw) and upper chest. However, distinctions can be made by observing the contrast inbuilt and overall body posture of both species.
With an average speed of about 6.5-10 km/h, King penguins are considered great swimmers, but on land, they depend on legs as well as their flippers-like wings to commute. Both Emperor and King penguins are flightless, like all other penguin species.
A Ruffled Weka | Image Courtesy: Newbie Pix/Flickr
Scientific Name: Gallirallus australis
Weka, one of the many extant rail species, is a flightless bird endemic to the island country of New Zealand. So far, four subspecies of Weka are recognized and are distinguished from each other by their slightly different color patterns.
Like other railbirds, Weka has small wings, with a maximum wingspan of 60 cm. It plays an important role in some Māori (indigenous Polynesians living in New Zealand) societies, who admire their fearless personality. Wekas were once used as a source of food and clothing.
2. Brown Mesite
A Brown Mesite in Madagascar
Scientific Name: Mesitornis unicolor
Brown Mesite is a flightless bird species found only in Madagascar’s humid evergreen forests. The Brown Mesite is classified as a vulnerable species. Due to its preference to remain in low altitude regions of the forest, where dogs and other common predators are widespread, they are an easy target to prey upon. Loss of habitat is also a major factor for their declining population.
A Kakapo on Maud Island, New Zealand | Department of Conservation
Scientific Name: Strigops habroptilus
With a total population of just 213 individuals, the Kakapo is a critically endangered bird species that are only found in New Zealand. It is one of the longest living birds and the only flightless parrot species on earth.
Compared to its body, a Kakapo has relatively small wings and tail. From an evolutionary standpoint, the Kakapo epitomize the tendency of bird species on islands to lose flying abilities in favor of bulky or sturdy body.
If not on the ground, Kakapos are found on trees as they are efficient climbers. Their wings, even though small and weak, allow Kakapos to glide down from trees.