The question “What bird flies upside down?” is an intriguing one that captures people’s curiosity about the natural world. While most birds fly with their bodies upright, there is one bird that is known for its ability to fly upside down: the Common Swift. In this article, we will explore the reasons why the Common Swift can fly upside down, how it achieves this aerial maneuver, and what advantages upside down flight offers this aerial acrobat. We’ll also look at some other birds that are able to fly inverted for short periods of time. So read on to learn all about the wonders of upside down bird flight!
What is the Common Swift?
The Common Swift (Apus apus) is a small bird in the swift family Apodidae. It is found throughout Europe and Asia and is known for its speedy flight and aerial agility. Some key facts about the Common Swift:
- Length: 16-17 cm
- Wingspan: 38-40 cm
- Weight: 42 grams
- Maximum speed in level flight: 69 mph
- Nest: Glues together twigs to make half-saucer shaped nest on vertical surface
- Diet: Insects caught in flight
The Common Swift spends almost its entire life airborne, living on the insects it catches while flying. It is a highly aerial species and is able to fly for hours without landing. This is an adaptation that allows it to feed continuously on the go.
How Does the Common Swift Fly Upside Down?
The Common Swift has specialized anatomy and flight skills that allow it to perform the remarkable stunt of inverted flight. Here are some of the key features that enable upside down flight in the swift:
Short Legs
The Common Swift has very short legs that are positioned far back on its body near the tail. This center of gravity allows the bird to easily perform aerial acrobatics, as its body is not encumbered by long, dangling legs. The short legs are mostly used for perching rather than walking.
Large Wings
The wings of the Common Swift are proportionally large compared to its body size. This gives the bird added lift and maneuverability in flight. The wing shape enables quick turning and allows sustained inverted flight.
Stiff Wing Feathers
The primary wing feathers of the Common Swift are stiffer than those of many other bird species. This prevents excessive drag on the upstroke that could destabilize inverted flight. The stiffness comes from increased keratin density in the feather shaft.
Rapid Wing Beats
In level flight, the Common Swift beats its wings up to 5 times per second. This rapid wing-flapping helps generate sufficient lift to keep its light body aloft. The fast wing beats continue even during upside down flying.
Rear-Facing Toes
Three of the Common Swift’s four toes face rearwards. This anatomy gives it a better grip strength on vertical surfaces where it nests. The toes also provide more stability in upside down perches.
Lightweight Body
Weighing just 42 grams on average, the Common Swift has a streamlined, lightweight body that minimizes drag in flight and enables agile aerial maneuvers. The light frame places less aerodynamic demands on the wings during inverted flight.
Bouyant Plumage
The Common Swift’s feathers contain spongy material that increases air retention. This makes the plumage more bouyant and reduces the effort needed to generate lift, facilitating extended flight and upside down aerial feats.
How Does the Common Swift Actually Fly Upside Down?
The Common Swift relies on some clever wing motions and positioning to achieve inverted flight:
Tilted Wings
The Common Swift angles its wings upward by around 15 degrees during normal upright flight. To transition into an inverted position, it then tilts its wings downward to a -15 degree angle instead. This wing tilt creates sufficient inverted lift to flip its body upside down.
Symmetrical Strokes
Most birds have asymmetrical wing strokes, with a shallow downward flap and a deeper upward recovery stroke. The Common Swift’s wingbeats are symmetrical, which provides even lift generation on both strokes to maintain inverted flight.
Elevators Deflected Upward
By deflecting its tail feathers upward, the Common Swift can increase lift at the rear of its body as it pitches into an inverted orientation. This elevator action stops the tail from dropping and stabilizes upside down flight.
Constant Speed
The Common Swift maintains its rapid wing flapping as it goes inverted. This constant speed keeps lift and momentum smooth throughout the transition to upside down flight. Sudden speed changes could cause an aerodynamic stall.
Sharp Banking Turns
Sharp vertical banking turns of up to 90 degrees allow the Common Swift to swiftly flip upside down with minimal loss of altitude. The rapid turn angles its lift directly into the desired inverted vector.
Fast Reaction Time
The Common Swift has super-fast reaction times in its wing muscles. This allows it to make instantaneous flight adjustments to control inverted maneuvers and counter any destabilizing wobbles.
Why Does the Common Swift Fly Upside Down?
This unique aerial talent of the Common Swift is not just a stunt – it serves some important purposes:
Chasing Aerial Prey
By rapidly transitioning to inverted flight, the Common Swift can keep small aerial insects within its sight while swiftly changing direction. This helps it successfully chase and capture food on the wing.
Dodging Predators
Some raptors hunt Common Swifts. By abruptly turning upside down, a swift can get out of the line of attack and avoid being struck by a diving predator. This maneuver can surprise the predator and allow the swift to escape.
Courtship Displays
Male Common Swifts sometimes perform upside down swoops and spirals to impress females during courtship. This aerobatic act demonstrates the male’s flying skill and fitness.
Righting When Thrown Off Balance
If turbulence or a collision throws it off balance, the Common Swift can quickly right itself by inverting then re-inverting. This prevents an uncontrolled spiral toward the ground.
Adjusting to Crosswinds
By banking inverted, the Common Swift can counteract being blown sideways off course by crosswinds. This allows it to maintain a straightheading.
Resting One Wing at a Time
The Common Swift can alternate between inverted and upright flight to give each wing a break in turn. This may allow it to rest its wing muscles while still airborne.
How Do Young Common Swifts Learn to Fly Upside Down?
Fledgling Common Swifts must rapidly master the art of inverted flight through the following methods:
Instinct
Even before their first flight, Common Swift chicks already have an innate sense of balance and roll coordination. They have the basic instincts required to perform aerial somersaults.
Playful Practice
Fledgling swifts will playfully chase each other while flapping their growing wings. This helps them develop initial control for tilting, banking, and rolling.
Parental Demonstrations
Young swifts watch their parents fly upside down to catch food and right themselves when knocked off balance. These demonstrations teach them real-world skills.
Repeated Attempts
At around 3 weeks after fledging, the young swifts begin trying inverted swoops and dives. Through repeated attempts, they hone control and timing.
Strengthening Flight Muscles
The constant aerial activity of young swifts builds the necessary flight muscles in their shoulders and chest to master upside down flying. This takes sustained practice.
Maturing Neurology
As their brains and motor control regions mature, fledgling swifts gain the neurology needed for complex aerial maneuvers and rapid in-flight adjustments.
Survival Motivation
The motivation to gain food and avoid danger drives young swifts to quickly perfect upside down flight – a skill necessary for their survival. This pushes them to progress.
What Other Birds Can Fly Upside Down?
While the Common Swift is the master of sustained inverted flight, some other agile bird species have also been observed performing full or partial upside down flight:
Hummingbirds
To impress females, courting male hummingbirds can execute inverted loops or pass underneath feeders in an upside down position.
Parrots
Many parrots are adept at aerial rolls and barrel rolls. Some can fly briefly upside down, especially if trained.
Ravens
Young ravens sometimes perform playful upside down swoops and flips while flying and chasing each other.
Cliff Swallows
Cliff swallows occasionally fly upside down when gathering mud nest materials to apparently keep an eye out for predators.
Frigatebirds
Male frigatebirds may fly upside down for short periods during their mating rituals to attract females.
Bird | Maximum Inverted Flight Duration |
---|---|
Common Swift | Over 1 minute |
Hummingbird | 5 seconds |
Parrot | 10 seconds |
Raven | 3 seconds |
Cliff Swallow | 4 seconds |
Frigatebird | 8 seconds |
As the table shows, no other bird comes close to matching the Common Swift’s aerial agility and ability to fly fully inverted for over a minute at a time.
Conclusion
The Common Swift is a remarkable bird that has evolved specialized skills and anatomy to achieve gravity-defying inverted flight. Key adaptations like back-facing toes, stiff wing feathers, a rear center of gravity, and rapid flapping allow this master of acrobatics to swiftly flip upside down with ease. Young swifts must practice extensively to gain control of inverted flying. While a few other nimble bird species can briefly fly upside down, the Common Swift remains the supreme aerial acrobat uniquely capable of sustained, controlled, upside down flight. So next time you see a small bird flying overhead, look closely – it just might be a Common Swift showing off its incredible aerial skills!