Hummingbirds are amazing little birds that have mastered the art of hovering in midair and flying backwards, making them one of the most agile and maneuverable birds on the planet. Their unusual flight capabilities are made possible by specialized adaptations likerapidly beating wings, light bodies, and an inverted flight stroke that generates both lift and thrust. While all hummingbirds exhibit unusual flight patterns, some species have taken it to the extreme and developed truly bizarre aerial abilities. Here we’ll explore some of the strangest and most fascinating hummingbird flight behaviors and how these tiny birds achieve such remarkable feats of flight.
How do hummingbirds hover?
Hovering in midair is one of the most recognizable features of hummingbird flight. Their wings beat incredibly fast, from 12 beats per second up to an astounding 80 beats per second. This allows them to generate enough lift to counteract the pull of gravity and stay suspended in one place.
Some key adaptations enable this specialized hovering ability:
- Wings that rotate in a figure-eight pattern during each beat
- Wing bones that flex and bend rather than remaining rigid
- Powerful breast muscles that account for 25-30% of their total body weight
- Feathers with stiff shafts and flexible tips that prevent airflow disruption
As the wings rotate, air flows over the top surface when moving forward and under the bottom surface when moving backward. This creates lift on both the upstroke and downstroke. The rapid wingbeats also generate thrust to propel the bird forward, backward, up and down.
Why can hummingbirds fly backwards?
Hummingbirds are the only birds that can truly fly backwards. They accomplish this by inverting their wings so the bottom surface faces forward during the backward stroke. This inverted flight stroke is unique to hummingbirds.
During normal forward flight, the wing moves forward and exerts lift while the bottom surface faces back. On the backward stroke, the wing exerts relatively little lift. But by inverting the wings, the bottom surface creates lift while moving backward. This allows hummingbirds to generate thrust in whichever direction they choose.
Being able to fly backwards comes in handy for maneuvering in tight spaces and hovering in place while accessing flowers. It also allows hummingbirds to show off their aerial skills.
How do they perform aerial courtship displays?
During courtship displays, male hummingbirds perform incredible aerial maneuvers to impress females. Two bizarre behaviors they exhibit are:
- The shuttle display – The bird flies back and forth in a U-shaped pattern while rapidly buzzing his wings. He may rise several feet and then dive back to his original position in an intricate shuttle display.
- The dive display – The bird flies as high as 100 feet in the air before folding his wings and diving sharply before pulling up at the last second.
These extreme dives and climbs require expert control enabled by specialized wing adaptations and muscles. Females observe these complex moves to assess the male’s flying skills as an indicator of fitness.
What is vortex surfing?
Vortex surfing is an unusual phenomenon seen in Anna’s hummingbirds where they ride conveyed in high-speed horizontal or vertical loops inside vortex bubbles created by their own wings.
As the hummingbird’s wings beat, they generate a circular vortex of rotating air – essentially a mini tornado attached to each wingtip. By precisely positioning their bodies inside one of these vortex bubbles, Anna’s hummingbirds can swiftly ride the leading edge of the vortex without expending additional energy.
Researchers using high-speed cameras discovered that males perform almost half of their complex shuttle displays by vortex surfing to execute rapid aerial loops. Females were also observed using vortex surfing when leaving flowers.
Why do hummingbirds fly high altitude migratory routes?
Though small, hummingbirds are incredibly strong long-distance migrants. Every year they undertake arduous journeys spanning hundreds to thousands of miles between their breeding and wintering grounds.
Most migratory hummingbirds choose an unconventional high altitude route for their travels. Here are some key reasons why:
- Higher altitude wind currents allow for faster transport over long distances.
- Far less predators and food competition at higher elevations.
- Less obstacles to navigate, allowing them to conserve energy.
- Cooler temperatures help prevent overheating their tiny bodies.
- More direct routes avoiding mountains and other barriers.
By riding high altitude tailwinds as high as 12,500 feet, hummingbirds are able to make nonstop flights over the Gulf of Mexico up to 23 hours long.
How do they fly in the rain?
Hummingbirds are capable of flying in a variety of weather conditions, including rain and wind. Their maneuverability comes in handy when battling the elements.
In heavy rain, they can beat their wings up to 70 times per second, allowing them to power through raindrops. Flexible tail feathers act as stabilizers to counteract gusts of wind.
Specialized leg and toe muscles enable hummingbirds to cling tightly to branches and flowers, even in driving rain or high winds. They conserve energy by entering a torpid state while waiting out storms overnight.
Interestingly, wet feathers don’t compromise their flying abilities. The fuzzy down feathers covering their body allow air to still flow smoothly over wet surface feathers. Water-repellent oil on their feathers also help repel rain.
How high and fast can they fly?
The speed and altitude records for hummingbird flight are extremely impressive considering their tiny size:
- Top horizontal speed: 34 mph
- Highest recorded altitude: 21,000 feet
- Fastest measured dive speed: 61 mph
- Average wing-flap rate: 50 flaps/second
- Maximum acceleration from rest: 60 g (60 times the force of gravity)
The highest altitude recorded was a Rufous hummingbird flying over the Rocky Mountains. Top dive speeds are achieved during courtship displays while the birds plummmet from heights up to 100 feet.
Their maximum horizontal speeds are close to the physiological speed limits for hummingbird flight. Researchers believe they cannot go much faster without their wings rupturing from aerodynamic drag forces.
How do they fly with only half their brain?
Hummingbirds have the remarkable and unusual ability to fly with only half of their brain awake and functioning. When they sleep, one half of the brain stays awake to control flight, while the other half sleeps. This is known as unihemispheric sleep.
Specializations that enable half-brain sleep include:
- Extra connections between the two brain hemispheres to coordinate signals
- A neck muscle that rocks the head from side-to-side to keep visual input steady
- Eyes that can move independently to track objects
By resting only one hemisphere at a time, hummingbirds can continue flying while still getting proper sleep. They are the only birds capable of this type of sleep pattern.
Conclusion
From hovering to flying backwards to traversing thousands of miles along migratory routes, hummingbirds are truly aerial masters. Their specialized wing design, muscle coordination, and physiological adaptations allow them to conquer a wide range of flight challenges. While all hummingbird flight appears unusual compared to other birds, some species have honed their skills to achieve truly remarkable feats in midair.
