Yes, there are some rare species of birds that are born without legs. Birds without legs are known as apodiformes, which means “without feet” in Latin. The most well-known legless birds are swifts and hummingbirds. These amazing creatures have evolved specialized adaptations that allow them to live fully functioning lives without ever touching the ground.
Swifts and hummingbirds belong to an order of birds called Apodiformes that have very short legs that are used primarily for perching rather than walking or hopping on the ground. Their feet are so tiny that they are basically vestigial and useless for walking.
So how do these legless birds get around without legs to walk or hop? They have beautifully designed wings that allow them to live life on the wing. Swifts and hummingbirds have the ability to hover, fly forwards, backwards, upwards, downwards, and make quick sharp turns with amazing agility. Their short stature, light bones, and unique wing design give them the aerobatic skills necessary to catch insects in midair and drink nectar from flowers while hovering motionless.
These legless birds exhibit some miraculous adaptations that allow them to eat, sleep, breed, and raise offspring without ever landing on the ground. Everything they need to survive and thrive is accomplished during continuous flight. Next we will look at some of the specialized features that allow these inspiring creatures to live such active airborne lifestyles.
Specialized Beaks
One of the most important adaptations for legless birds is the design of their beaks, which are perfectly shaped for grabbing insects out of the air or sipping nectar from flowers. A swift’s small beak has a large gape that is ideal for catching insects during fast aerial maneuvers. They snatch up flying insects like flies, mosquitoes, termites, ants, beetles, and aphids and swallow them whole without landing.
Hummingbirds have slender pointed beaks that are ideal for drinking nectar. Their long tongues have forked tips that lap up nectar. Some hummingbirds even have bendable tongue tips that they can flare out to reach deeper into certain trumpet shaped flowers. When not in use, hummingbirds’ tongues retract into grooves on the bottom of their beaks.
Swift Feet
While swifts and hummingbirds don’t use feet for walking, they do have specialized feet that help them cling to vertical surfaces. A swift’s short legs end in sharp curved claws that provide a vice-like grip around branches, tree trunks, rocky ledges, or chimneys. Hummingbirds’ feet also have sharp claws, usually only on the hind toes, allowing them to securely perch on branches and wires while feeding.
Both swifts and hummingbirds can also use their tail feathers like a prop to brace themselves against flat vertical surfaces. And hummingbirds have the unique ability to swivel their feet backwards into a reversed position to get a better distribution of weight for perching on overhangs.
Short, Stiff Wings
The short rounded wings of swifts and hummingbirds allow them to generate the high frequency wing beats necessary for sustained hovering and rapid flight. The stiffness of their flight feathers gives the wings structural strength despite their small size.
Specialized muscles and tendons allow them to rotate their wings in almost any direction – flapping, gliding, diving, and rapid turning. At up to 80 wing beats per second, hummingbird wings are simply a blur. Variations in wing shape between the around 350 species provide adaptations for different flying and feeding styles.
Lightweight Bones
One important adaptation that allows swifts and hummingbirds to maintain continual flight is having an extremely lightweight skeleton. Their bones, especially in the wings, are thin, hollow, and fragile. With less weight to carry, their flight muscles can operate at high frequencies with less effort.
Excellent Eyesight
Swifts and hummingbirds also have excellent vision to spot food and maneuver while flying. They have large eyes relative to their head size and can see colors humans can’t even perceive. Specialized eye muscles allow them to rapidly focus on objects at different distances. This exceptional eyesight gives them the visual acuity needed to locate tiny insects and flowers during rapid flight.
Tiny Nestlings
Baby swifts and hummingbirds that hatch from eggs are almost naked, blind, and totally helpless. But with no need to use legs or walk around, they survive by basically just opening their mouth wide to be fed by the parents. Their tiny size, fast growth, and insatiable appetites are the only things that matter until they can fly on their own.
Sleeping on the Wing
Swifts and hummingbirds have even evolved the remarkable ability to sleep while flying. They enter periods of light, unrestful sleep where their brain hemisphere slows down alternately. This allows the sleeping half to rest while the awake half continues their flying maneuvers uninterrupted. They ascend high in the sky where air currents keep them afloat, and may even slow their heart rate.
Aerial Mating
Swifts and hummingbirds unique lifestyles extend to their mating rituals, which of course happen midair. Courtship displays involve aerial pursuits with males showing off their flying skills. Mating happens with the birds perched together on branches or while the male grips the female in midair. The actual transfer of sperm occurs very quickly, in just a fraction of a second.
Flying Nest Builders
Swifts and hummingbirds use unique strategies for gathering materials and constructing nests without landing on the ground. Hummingbirds build tiny cup-shaped nests out of soft materials like plant down, spider webs, lichen, and moss that they collect while hovering. They use spider silk to stitch the materials together and secure the nests to branches.
Swifts build half-saucer shaped nests plastered to vertical cliffs and cave walls made of twigs, branches, leaves, feathers, and mud that they break off and catch while flying. The nest materials are glued together with the birds’ sticky saliva produced by enlarged salivary glands.
Aerial Parents
Since they never land, swifts and hummingbirds have evolved techniques for caring for eggs and raising hatchlings entirely during continuous flight. For incubation, they must rely on their featherless bellies and breast muscles to provide warmth to eggs developing in nests.
Baby swifts and hummingbirds are fed with the parents’ beaks by regurgitating insect parts or nectar. The aerial parents collect food on the wing and return to briefly hover and stick their heads into the nest to deliver meals straight into the gaping mouths of their ravenous offspring.
Migration Marvels
Many swifts and hummingbirds migrate long distances each year between breeding and wintering grounds. They fly tirelessly across oceans, deserts, and mountains through all types of weather. Reddish Shearwaters even make a figure eight migration loop across the Pacific and Atlantic oceans totaling about 40,000 miles each year.
ruby-throated hummingbirds weighing only a few grams fly nonstop 600 miles across the Gulf of Mexico. The Black Swift holds the record for the highest bird flight ever recorded at over 21,000 feet above sea level over Mt. Shasta. These mighty migrants provide some of the most extreme examples of aerial endurance in the animal kingdom.
Incredible Mobility
Legless birds like swifts and hummingbirds are capable of seemingly impossible aerial maneuvers. They can fly straight up, down, backwards, upside down, and bank or turn on a dime. Their ability to hover motionless provides them access to food sources unreachable by other birds.
All their fantastic abilities are enabled by their specialized adaptations for life in the fast lane. These tiny birds demonstrate that a lack of legs has not inhibited their survival or evolutionary success. If anything, the loss of legs has only expanded the limits of their potential through the magnificent capabilities of flight.
Examples of Legless Birds
Here are some specific examples of birds that are born without legs and feet or have only small non-functional legs:
Swifts
– Common Swift: This widespread species breeds across Europe and Asia in colonies nesting on cliffs and buildings. They are powerful fliers that can stay airborne for nearly 10 months nonstop.
– White-throated Needletail: Found in Asia and Australia, these swifts are one of the world’s fastest birds capable of reaching speeds over 105 mph in level flight. They feed on insects caught in continuous aerial pursuits.
– Chimney Swift: Native to North America, these swifts roost and nest communally in chimneys and build bracket-shaped nests out of twigs glued with saliva to vertical walls. Their short legs are covered in sharp bristles.
Hummingbirds
– Bee Hummingbird: Found only in Cuba, this tiny bird is the smallest existing species of bird in the world, measuring just 2 inches long and weighing 1.6 grams. Their feet are minuscule and unable to walk.
– Ruby-throated Hummingbird: This familiar backyard hummingbird of North America hovers at flowers and feeders. Males perform elaborate courtship displays and make fast dives to impress females. They have small weak feet for perching only.
– Andean Hillstar: Found in South America, this mountain species has an extra-long tail and bright iridescent plumage. Their short legs and tiny feet are not designed for walking or hopping.
Other Legless Birds
– Swiftlet: Found in Southeast Asia, these small cigara-shaped birds nest in caves and navigate using echolocation inside the dark caves. They have small feathered legs and short rounded wings ideal for continuous flight even while sleeping.
– Treeswifts: This group of swifts endemic to tropical forests in Asia and Africa have claw-tipped tails that act like a fifth limb to grip branches. With tiny feathered legs, they never descend to the ground, even bathing aerially by flying through waterfalls.
Legless Birds vs Flightless Birds
While a small number of bird species like swifts and hummingbirds have evolved to live without functional legs and lost the ability to walk or hop, some birds have gone the opposite route and lost the ability to fly due to evolutionary adaptations. These flightless bird species have often evolved robust leg bones and feet for running or swimming.
Some examples of well-known flightless birds include:
– Ostrich – Large flightless bird of Africa that is the largest living bird species, weighing up to 350 pounds. They have powerful legs used for running up to 43 mph.
– Emu – Flightless birds found in Australia that reach heights of 6 feet. They have small vestigial wings and three-toed feet specialized for running.
– Penguin – Aquatic flightless birds of the southern hemisphere. Their wings evolved into flippers for swimming and they use feet for waddling on land.
– Kiwi – Nocturnal flightless birds of New Zealand. They have a reduced keeled sternum and small vestigial wings with no flight feathers. They have strong legs and a long beak for probing the ground.
– Cassowary – Large flightless birds of New Guinea and Australia related to emus. They have stiff quills instead of flight feathers on vestigial wings and can kick and leap with clawed feet.
So while swifts and hummingbirds represent examples of birds that have taken to the extremes of aerial living, flightless birds illustrate the opposite adaptation of reverting to robust terrestrial limbs for ground mobility when the pressures of flight are removed.
Conclusion
In conclusion, there are a small number of amazing bird species that are born without functional legs and spend their entire lives in flight. Swifts, hummingbirds, and other Apodiformes exhibit specialized adaptations like short wings, claws for clinging, sight for aerial feeding, and flying sleep and mating that enable a foot-free existence. These legless birds demonstrate how evolution can produce radical adaptations in response to ecological pressures and that wings can fully substitute for legs in birds. So while most birds need legs for moving on the ground, some unique species have taken to the skies exclusively and proven that a bird can live a rich active life through flight alone.