The pallid swift (Apus pallidus) is a small bird found across parts of Africa and Asia that is known for its speedy flight. This article will examine key questions around how fast the pallid swift can fly and what enables it to reach such high speeds.
How does the pallid swift fly so fast?
The pallid swift is built for speed. It has long, curved wings that give it great aerodynamics. Its light, slender body and short tail reduce drag. The pallid swift also has special adaptations like a shortened humerus bone in their wings which allow them to flap their wings very quickly.
Research has found the pallid swift can flap its wings up to 25 times per second. This rapid flapping creates the lift and thrust to propel them quickly through the air.
Wing structure
The pallid swift’s long, curved wings are perfectly shaped to generate lift and reduce drag as the birds fly. The wings are long and narrow which maximizes the lift-to-drag ratio. The swept-back shape also reduces drag from wingtip vortices. The wingtips are also reinforced to withstand the aerodynamic forces.
Lightweight body
Weighing only around 85 grams on average, the pallid swift has an extremely lightweight body. Their bones are hollow and their feathers are very fine. This light weight means they can flap their wings very quickly and accelerate rapidly with less effort.
Short tail
The short, forked tail of the pallid swift reduces drag and allows faster flight. The tail helps provide stability but its shortened length cuts back on the drag that would be caused by longer tail feathers.
What speeds can the pallid swift reach in flight?
Research using radar technology and video analysis has found pallid swifts can reach extremely fast speeds in flight:
- Cruising speed: Around 35 mph (15-17 m/s)
- Maximum speed: Over 100 mph (over 45 m/s)
Pallid swifts beat their wings up to 25 times per second and take nearly 200 wingbeats to cover 100 meters when flying fast. This rapid flapping propels them to speeds over 4 times their body length per second.
Fastest measured speed
One study that analyzed video footage of pallid swifts in flight recorded a maximum speed of 111 mph (50 m/s) – one of the fastest speeds ever measured for a bird.
Speed range
While pallid swifts can reach over 100 mph in bursts, most of their routine flying is done at cruising speeds of 25-35 mph based on research. But they can accelerate rapidly when needed for pursuing prey or display flights.
How does the pallid swift’s speed compare to other birds?
The pallid swift is considered one of the fastest flying bird species in the world. Here is how it compares to some other fast birds:
| Bird | Maximum Speed |
|---|---|
| Pallid swift | 111 mph |
| White-throated needletail | 105 mph |
| Frigatebird | 95 mph |
| Peregrine falcon | 200 mph (diving) |
The peregrine falcon can reach over 200 mph when diving to catch prey, making it the fastest animal on Earth. But in level, powered flight, the pallid swift is among the fastest of birds.
Faster than other swifts
The pallid swift can fly faster than even related swift species. For example, the common swift has been measured flying at 69 mph at top speed.
Enabling speed
Specialized adaptations like their crescent-shaped wings, stiff tail feathers, and short legs allow the pallid swift to fly faster than many other birds.
Why does the pallid swift fly so fast?
The pallid swift’s speed serves several important purposes:
- Chasing prey – They can reach fast speeds to pursue flying insects
- Avoiding predators – Their speed helps them escape from predators
- Migration – They migrate long distances quickly
- Mating displays – Fast flights help them impress mates
Catching insect prey
Aerial insects like flies, mosquitoes, and termites make up the bulk of the pallid swift’s diet. Reaching speeds over 100 mph allows pallid swifts to swiftly chase down and capture fast-flying insect prey.
Predator evasion
With dangerous predators like falcons and hawks to contend with, pallid swifts rely on rapid acceleration and speed to escape being caught by predators.
Long distance migration
Pallid swifts migrate thousands of miles between Africa and Asia. Flying at fast cruising speeds allows them to complete these lengthy seasonal migrations more efficiently.
Impressing mates
Male pallid swifts perform elaborate mating displays in flight to attract females. Being able to fly quickly and nimbly shows off their flying skills.
How do pallid swifts fly so fast for so long?
Pallid swifts have incredible stamina to fly at fast speeds for extended periods:
- They can spend up to 10 months continuously on the wing after leaving the nest.
- They feed and sleep while airborne – eating aerial insects and apparently sleeping on the wing.
- High metabolism and oxygen intake enables their endurance.
- They have energy-rich diets when insects are abundant.
Months in flight
Young pallid swifts may spend 2-3 years flying nonstop after first leaving the nest. Their entire lives are spent on the wing except for breeding.
Aerial living
These swifts can sleep in short bursts while gliding and ascend high in the evening to feed on insects drawn upwards by convection currents.
High metabolism
Pallid swifts have a metabolic rate nearly twice as high as similar-sized birds. They also have larger hearts and consume more oxygen, powering their flight muscles.
Energy-rich diet
When insect prey is abundant, pallid swifts can build up fat reserves providing energy to sustain their endurance flights.
Do pallid swifts ever stop flying?
Pallid swifts are almost entirely aerial except for a few instances when they briefly land:
- Breeding – They nest in crevices and ledges on cliffs and buildings where they briefly land 2-3 times per year to breed.
- Nestlings – Young pallid swifts cannot fly for their first month and remain in the nest.
- Resting – They may rarely stop to briefly rest on vertical surfaces but not for more than a few minutes.
- Roosting – Some populations have been observed landing in treetops to roost at night.
Brief breeding season landings
When nesting, pallid swifts land just long enough to construct nests, mate, and care for nestlings before taking off again.
Grounded nestlings
Newly hatched pallid swifts cannot fly for their first 4-6 weeks of life. They remain grounded in nests where the parents feed them.
Rare resting
Healthy pallid swifts in flight rarely need to stop to rest and may just briefly perch vertically on cliffs or buildings.
Overnight roosting
In some parts of their range, pallid swifts have been documented landing in treetops at dusk to rest overnight before resuming flight at dawn.
How does the pallid swift fly so well?
Several key adaptations enable the pallid swift’s superb flying abilities:
- Crescent-shaped wings – Provide lift and reduce drag
- Stiff tail feathers – Stabilize and steer
- Short legs – Reduce drag and shift center of mass forward
- Compact body – Cuts through the air with minimal resistance
- Keen vision – Helps track prey and avoid obstacles
Crescent wings
The pallid swift’s sharply curved wings allow air to flow smoothly over the wing surface, generating optimal lift with minimal turbulence.
Stiff tail
The pallid swift’s forked tail has stiff streamer feathers that remain fully extended in flight to provide stability and steering.
Tiny legs
With their tiny legs drawn up against their bodies, pallid swifts present a clean, aerodynamic profile with minimal protruding limbs.
Streamlined shape
The pallid swift’s smooth, compact body shape cuts through the air allowing swift, agile flight.
Eagle-eyed vision
Exceptional vision equips pallid swifts to deftly catch tiny insect prey and rapidly adjust their flight to avoid collisions.
How does the pallid swift change speed and direction?
Pallid swifts maneuver with lightning-fast precision thanks to their specialized physiology:
- Rapid wingbeats – Allow instant speed bursts
- Asymmetrical wing moves – Enable tight turns
- Fanned tail – Helps brake and steer
- Low wing loading – Permits quick maneuvers
Fast wing flapping
By beating their wings up to 25 times per second, pallid swifts can swiftly accelerate and vary speed.
One-sided wing flapping
Flapping just one wing while gliding the other allows tight turns and rolls.
Tail-fanning
Fanning their forked tail provides braking and helps them deftly bank and turn.
Agile wings
A low wing loading ratio (wingspan vs. body weight) gives their wings high agility for rapid changes of speed and direction.
How is the pallid swift adapted to life in the air?
After evolving for a strictly aerial life, the pallid swift displays remarkable adaptations:
| Adaptation | Description | Flight Advantage |
|---|---|---|
| Crescent-shaped wings | Long, curved wings provide lift and reduce drag | Efficient flight and gliding |
| Compact, lightweight body | Low body weight and streamlined shape cut drag | Swift, agile flight |
| Wide gape | Large mouth gapes to catch insects in flight | Aerial feeding without landing |
| Short legs | Minimal protruding limbs reduce drag | More streamlined profile |
| Keen vision | Exceptional visual acuity to navigate and find food | Spotting prey and avoiding collisions |
Aerodynamic wings
The pallid swift’s curved wings allow smooth passage through the air supporting sustained flapping flight.
Light and fast body
With hollow, lightweight bones and streamlined feathers, the pallid swift’s body is optimized for speed and efficiency in flight.
Wide gaping mouth
Their enormous gape facilitates catching insects on the wing so they can feed during continuous flight.
Tiny legs
With their minuscule legs drawn in during flight, their silhouette is tidy and aerodynamic.
Eagle-eyed sight
Able to spot tiny insects hundreds of feet away, their vision also helps avoid collisions and track mates.
How do young pallid swifts learn to fly so well?
Despite their innate flying instincts, young pallid swifts still must develop their expertise through practice and guidance:
- First flights – Tentative early flying attempts near the nest improve skills.
- Parental guidance – Parents demonstrate expert technique to fledglings.
- Play behavior – Young birds hone skills through aerobatic play.
- Experience – Their skills refine over months and years of constant flight.
Shaky first flights
For their first flights, fledgling pallid swifts make short practice flights near their nests to build flying strength and coordination.
Following parents
As parents forage, young birds follow them closely, observing and mimicking their smooth, agile flight.
Playful skill-building
Fledglings also boost their abilities by play-chasing each other and performing elaborate aerial maneuvers.
Improving with time
With months and years of sustained daily flight, young pallid swifts refine their flying prowess.
Conclusion
With its superbly adapted physiology allowing remarkable speed and aerial agility, the pallid swift stands out as one of the most aerial-adept birds on Earth. While many birds fly fast or skillfully, the pallid swift excels at both thanks to its scythe-like wings, compact build, and keen vision guiding its every move. After evolving for life on the wing, this bird is a pure flying machine.
