pininterst email icon

Flight of the Hummingbird

Hummingbirds' aerial aptitude have impressed and inspired both New World inhabitants and Old World migrants alike—their cultures representing them as spirit world visitors, as symbols of flight, or the source of technological innovation. Some liken their abilities to those of insects. Nevertheless, distinguishing their flight from other birds is an impressive repertoire of flying abilities: aerobatics, quick acceleration, speed, and endurance. Hummingbird flying talents are the result of unique anatomical adaptations, biomechanics and, and physiology.

Levitating, flying erect, backwards, up, down, upside down, and backwards crown their repertoire. Finely tuned hovering—an aptitude in which it excels over other birds—allows micro changes of position in any direction or allows them to linger motionlessly. Often when maneuvering to a flower, they fly forward, erect—a considerable proportion of their flying is in this fashion, unlike other birds that fly mostly flat—in level flight an imaginary line from a bird's rump to the base of the beak roughly parallels the horizon—and then hang stationary to access its inner recess. Subsequently, retreat backward averting further and unnecessary contact. Then again they may remain suspended before hovering up or down to another blossom. When engaged in combat amongst themselves they often twirl about each other erect and, again, sometimes upside down then right-side up. During courtship, some males make high-speed dives from on high to impress female hummers.

Sometimes sallying from perches to fend off intruders to their territory or to approach blooms and at other times they skip from flower to flower. Once more, from perches or whilst hovering, they can flit along, in an instant, and disappear in a blur, in the distance. They cruise at speeds of at least ‪12.5‬ metres per second or 45km per hour (30mi per hour) but can reach speeds in excess of 85km per hour (53mi per hour)[1].

‬‬‬‬

Although hummingbirds can sidle along a branch, even for short distance they take to the wing. One might consider that their endowment of flight has weakened their legs or that their flying ability partly compensates for weak legs. Some have advanced that underdeveloped legs enhance their aerodynamics.

Hummingbirds have mastered long-distance flight and endure migrations over thousands of miles. The rufous hummingbird migrates at least 2,000 miles and as much as 3,900 miles from Mexico to northwest United States, British Columbia, and Alaska. Ruby-throated hummingbird migrate south along the American east coast to Mexico, some take an inland route whilst some traverse the Gulf of Mexico, crossing 800km (500mi) - 1000km (621mi); others present as vagrants after island hopping, over distances as much as 90 miles, to Cuba, also to The Bahamas, Jamaica, Hispaniola, and Puerto Rico. Other species show up as vagrants on other islands outside of their breeding range having ventured open seas. For example, the green-throated Carib a denizen of Windward and Leeward Islands occasionally present, further south, in Trinidad and Tobago. The purple-throated Carib also resident in the Lesser Antilles presents as a vagrant in northeastern Brazil. The green-breasted mango is a vagrant in Puerto Rico although the nearest breeding site is over 500 miles away in Venezuela.

The wing beat of hummingbirds is absolutely fast and faster than other birds. Smaller hummingbirds have a faster wing beat than larger ones. For instance, the amethyst woodstar has a measured wing beat of 70 to 80 per second. Medium-sized hummers wings beat at a rate of 20 to 30 per second. The giant hummingbird, a large hummer, has a wing beat of 10 to 15 per second.

Laterally, in direct flight, the wingtips of the hummingbird describe an ellipse [2],[a]. While hovering the hummingbird wing rotates 180 degrees[3]—they are inverted—and each wing (the tips) describes a figure eight. The down (forward) stroke generates 75% of its lift while the up (backward) stroke generates 25% [4]. Altering its wing angle enables a hummingbird to hover in place or to maneuver in any direction. Tail action enhances this maneuverability, braking, and control. Whilst, the tail facilitates balance during abrupt directional changes and switching from hovering to movement; during direct flight, it participates aerodynamically in ascents.

Their abilities are the result of the participation of several anatomical adaptations relating to the wing, shoulder, sternum, muscles, feathers, and tail. The wing attaches at the shoulder with a ball and socket joint that facilitate its rotation[5],[b]—the source of its maverick wing action. Hummingbird wings are faintly cambered[6]— a stronger camber, like in other bird species, is a drawback for hummingbirds—cambered (convex upward) wings provide lift when the leading edge cuts through the air in the direction of flight—pointed, relatively long, narrow, and bladelike[5]. The wing's arm (humerus) is very short in comparison to the rest of its forelimb, hand (manus) and forearm[7], and relative to the short arms of other bird species. Its hand is the greater part of the forelimb and is proportionally longer than the hands in a pigeon. This wing design is suited to its maneuverability[8] and essentially powered lift—via low-pressure vortices formed over the leading edges of the actuated wings[2]. Its sternum, to which the flight muscles attach, is comparably longer than in most birds. It supports the large flight muscles the pectoralis majors—a skeletal muscle that draws in and rotates the arm—and supracoracoideus muscles—a muscle that raises the arm and which is relatively larger in hummingbirds because of the powered upstroke[8]. These muscles are made of red fiber that supports endurance. Similar muscles in other birds are of white fiber that is suited for brief energy bursts[8]. Like passerine birds the hummingbird has ten primary feathers. However, it has the least number of secondary feathers, six, amongst birds—typically secondary feathers are the source of the cambered shape to a bird's wing. Hummingbirds have five pairs of tail feathers (one species has two)[9] contrasting with most bird species that have six pairs—a deficit consistent with a diminished role that hummer's tail play in maneuverability and control[9].

In support of their rapid wing beat hummingbirds have a high metabolism—the highest in the animal kingdom. Their heart rate can reach as high as 21 beats per second. Consequently, they must consume in excess of their body weight in nectar daily, which involves a lot of flying from flower to flower. This flying increases their energy demands—a perpetual cycle.

The flight abilities of the hummingbird have inspired high technology. The Nano Air Vehicle (NAV), a miniscule hummingbird-like aircraft, with a 6.3 inch (160mm) wingspan and weighing .67 ounces (19g), can ascend and descend vertically, hover, proceed sideways, backwards and forwards and swivel in flight. Like a hummingbird, its lift, propulsion, and control are achieved by agitating of its wings. It can reach speeds of 11 miles per hour (18km/h). Defense Advanced Research Projects Agency (DARPA), of the US, commissioned AeroVironment—a manufacturer of unmanned aircraft systems— to develop the vehicle that can operate remotely, without connection to an external power source, carry a video camera, hover, even in wind gust of up to 5 miles per hour, for up to eight minutes, and transition from hover to translational flight

There are other noteworthy imitating, technological innovations. Tyer Wind produces a residential wind turbine inspired by the hummingbird's hovering ability—it mimics the bird's figure 8 agitating motion— and its energy efficiency. Hiroshi Ryu of Japan's Chiba University—who says '...First, we need to learn about effective mechanism from natural life forms...'— has developed a flying robot of comparable size and weight, 2.6 grams (0.09 ounces), to a hummingbird; it can agitate its wings 30 times per second; rotate on its axes; and maintain stability whilst negotiating a figure-eight course. In the future, the archetype craft will be equipped with a micro camera and possibly be employed in surveillance, rescue missions, and the hunt for criminals.

Notes:

aIn direct flight the characteristic bird employs either a glide or wing-flaps. In a glide, lift is achieved by airflow over the outstretched cambered wing and propulsion by gravitational forces. When soaring, a modified glide, the wings are again outstretched but the lift is principally achieved by riding updrafts (thermals) and propulsion, again, by gravity. Wing-flaps generate lift and power with upstrokes and downstrokes, i.e., by moving the wing moves up and down. Most of the lift and thrust is generated during the downstroke. The outer wing's angle of attack is adjusted down to generate forward thrust by aerodynamic lift. During the upstroke the wing is partly folded, reducing drag, and the primaries are feathered, allowing air flow. The inner wing experiences minimal displacement during wing beats and provides aerodynamic lift throughout[10].

bIn a typical bird the wing attaches to the torso where the upper arm (humerus) connects, via ligaments, with a cartilaginous shallow bowl of the shoulder blade (scapula), the coracoid (a bone linking the scapula to the sternum), and clavicle (collarbone). In addition, a pectoralis ligament communicates the wrist to the front of the pectoralis—a chest muscle; also extending from the shoulder to the wrist is an elastic stretch of skin called the propatagium that aid in glided flight and, with the same makeup and function, and less pronounced, at the trailing edge the metapatagium links the elbow to the proximal flank[11].



AeroVironment Nano Hummingbird



Works Cited

1. PRUM, Ann Johnson. Hummingbirds: Magic in the Air. [prod.] Ann Johnson Prum. Public Broadcasting Service (PBS): Nature, 2009.

2. TOBALSKE, Bret W. , Douglas R. Warrick, Christopher J. Clark, et al. Three-dimensional kinematics of hummingbird flight. [Online] 2007. [Cited: December 20, 2018.] http://dx.doi.org/10.1242/jeb.005686.

3. Mitton, Jeff. Hovering Iridescence. College of Arts & Science. [Online] Colorado Arts & Science Magazine, 2009. [Cited: March 22, 2014.] http://artsandsciences.colorado.edu/magazine/?p=2246.

4. Oregon State University. Hummingbird Flight an Evolutionary Marvel. Phys.org. [Online] 2005. [Cited: December 4, 2018.] https://phys.org/news/2005-06-hummingbird-flight-evolutionary-marvel.html#nRlv.

5. Encyclopedia Britannica. Hummingbird. London : Encyclopedia Britannica, 2003. pp. 144-145. Vol. 6.

6. SAVILE, D. B. O. The Flight Mechanism of Swifts and Hummingbirds. SORA. [Online] 1950. [Cited: December 18, 2018.] Pages: 499-504. https://sora.unm.edu/sites/default/files/journals/auk/v067n04/p0499-p0504.pdf.

7. ZUSI, Richard L. Introduction to the Skeleton of Hummingbirds (Aves: Apodiformes, Trochilidae) in Functional and. BioOne. [Online] September 2013. [Cited: December 14, 2018.] https://doi.org/10.1525/om.2013.77.1.1.

8. Encyclopedia Britannica. Birds. London : Encyclopedia Britannica, 2003. pp. 1-7. Vol. 15.

9. Virutal Museum of Canada. Locomotion. Virutal Museum of Canada. [Online] Virutal Museum of Canada, 2007. [Cited: October 9, 2018.] http://www.virtualmuseum.ca/sgc-cms/expositions-exhibitions/colibri-hummingbird/En/Hummingbird/The-Life-Of-The-Hummingbird/locomotion.html.

10. DVOŘÁK, Rudolf. Aerodynamics of Bird Flight. EPJ Web of Conferences 114, 01001. [Online] 2016. [Cited: December 14, 2018.] http://dx.doi.org/10.1051/epjconf/201611401001.

11. MACWHIRTER, Patricia. Coracoid. ScienceDirect. [Online] ScienceDirect, 2009. [Cited: December 8, 2018.] https://www.sciencedirect.com/topics/veterinary-science-and-veterinary-medicine/coracoid.