Hummingbirds fly. That sounds redundant but includes what they do NOT do. Almost all hummingbirds do not walk or hop4 as other birds do. A female hummingbird will not even stand up and rotate her place to care for her eggs. She would rather fly. She will lift up off her nest, shift her position and hover back down. Hummingbird feet allow them to perch and balance but their strength is flight.2
Hummingbird flight is more diverse than other kinds of flight. There are evolutionary strengths that allow hummingbirds to fly forward, in reverse and maneuver sideways as breezes blow the flowers. A scientific test showed that hummingbirds are able to hover for as much as 50 minutes in one place – a strength that allows them to gather nectars tirelessly.2
Hummingbirds also stop and accelerate instantly, lift straight up and down and pivot while hovering. Hummingbirds can even escape quickly from a flower by flipping into a backwards summersault where they briefly fly in reverse while upside down!7
Hummingbird wings are affectionately called “hands” because the wing bone structure is all hand bone.12 The elbow and wrist joints of hummingbirds are rigid and so the wing does not bend or fold in the middle but remains straight out from the body in flight.10
When a hummingbird flies forward, it's wings beat up and down in a very slight circling motion. The wing is constructed of mostly primary feathers and the tilt and rotation at the shoulder allows the up-stroke to propel the hummingbird forward with as much force as the down-stroke.
This means that a hummingbird has two thrust strokes to every one of another bird. In other birds, the upstroke is a passive stroke – designed only to lift the wing into position.7
In order to hover, a hummingbird's wings move back and forth horizontally... drawing a narrow but elegant figure eight in the air with each full stroke. The stroke is continuous – like a Mobius strip – which is the symbol of infinity.1
You could repeat the hovering motion of hummingbird wings by holding your own arms straight out from the body and parallel to the floor. Turn your palms down. Imitate hummingbird wings by sweeping your arms forward with the thumbs leading the way.
To continue into a hovering back-stroke, your hands roll up and over. The whole arm sweeps backward with your palms to the sky, thumbs still leading the way. One full cycle of a hummingbird wing beat is completed when your arms reach back behind the body as far as they can go - and then the thumbs roll up and flip over again.10 Your palms are turned down, arms sweeping forward into the next stroke of infinity flight.
This unusual wing posture and movement is sustained by very strong breast muscles. An evolution particular to the hummingbird has made the muscles that elevate the wing (or up-stroke) as strong as the muscles that depress the wing (or down-stroke.) Add amazing rotation to the hummingbird shoulder joint (nearly 180°) and you have a forward and backward moving wing with precision control.7
The balance of muscle strength is exactly what allows every hummingbird to hover. The propulsion of the forward stroke is nullified by the reverse propulsion of the backstroke.2 There is enough force to cause lift but direction is kept in stasis until the hummingbird chooses otherwise.8
It is the double wing-stroke that provides abrupt swiftness and the characteristic “hum” of hummingbirds. For years it was thought that the humming hummingbird would beat its wings faster than other birds. Now we know that this is an illusion. When you compensate for body weight and wing length, hummingbird wings often move slower than other birds.
There are times when the hummingbird wing beat lives up to our expectation. When the male ruby-throated hummingbird is mating, its wings will accelerate and have been measured as much as 200 bps during an aerial display. This is the highest beats per second of any bird – but it is only brief.8
Another illusion is that hummingbirds fly faster than most other birds. Appearances account for this misunderstanding. Because they are so small, when hummingbirds fly you can barely see them and this seems very fast.
The fastest flying birds are the peregrine falcon, which drops down on it's prey at 175 mph,10 and the Duck Hawk measured at 160-180 mph.12 A scientific study measured the forward speed of a ruby-throated hummingbird at 27 mph and other reports have clocked hummingbirds in the wild at 40 mph and even 60 mph during courtship.
It only takes 1/500th of a second for a hummingbird to complete a wing beat cycle and only three cycles for hummingbird flight to occur.10 It is no wonder that hummingbirds are fearless. It is no wonder that hummingbirds come into our gardens and sometimes hover in arms reach. Their aerial fineness is perfect protection and grace.
There are researchers who believe that hummingbirds did not evolve from other birds (swifts) but developed their own bodies for specialized flight. These scientists have created a separate order just for hummingbirds called “Trochiliformes,” which recognizes the hummingbird as the highest evolution of all the non perching birds.8