Jump to content

Hummingbird

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by 71.102.76.247 (talk) at 02:49, 17 October 2009 (→Diet). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

For other uses, see Hummingbird (disambiguation).

Hummingbird
Female Black-chinned Hummingbird
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Aves
Subclass:
Neornithes
Infraclass:
Neognathae
(unranked):
Cypselomorphae
Order:
Apodiformes
Family:
Trochilidae

Vigors, 1825
Subfamilies

Phaethornithinae
Trochilinae

For a taxonomic list of genera, see:

For an alphabetic species list, see:

Hummingbirds are among the smallest of birds, and include the smallest extant bird species, the Bee Hummingbirds. They can hover in mid-air by rapidly flapping their wings 12-90 times per second (depending on the species). They can also fly backwards, and are the only group of birds able to do so.[1] Their English name derives from the characteristic hum made by their rapid wing beats. They can fly at speeds exceeding 15 m/s (54 km/h, 34 mi/h).[2]

Many plants pollinated by hummingbirds produce flowers in shades of red, orange, and bright pink, though the birds will take nectar from flowers of many colors. Hummingbirds can see wavelengths into the near-ultraviolet, but their flowers do not reflect these wavelengths as many insect-pollinated flowers do. This narrow color spectrum may render hummingbird-pollinated flowers relatively inconspicuous to most insects, thereby reducing nectar robbing.[3][4] Hummingbird-pollinated flowers also produce relatively weak nectar (averaging 25% sugars w/w) containing high concentrations of sucrose, whereas insect-pollinated flowers typically produce more concentrated nectars dominated by fructose and glucose.[5]

Aerodynamics of flight

A trail of wake vortices generated by a hummingbird's flight. Discovered after training a bird to fly through a cloud of neutrally buoyant helium-filled soap bubbles and recording airflows in the wake with stereo photography.[6]

Hummingbird flight has been studied intensively from an aerodynamic perspective using wind tunnels and high-speed video cameras.

Writing in Nature, the biomechanist Douglas Warrick and coworkers studied the Rufous Hummingbird, Selasphorus rufus, in a wind tunnel using particle image velocimetry techniques and investigated the lift generated on the bird's upstroke and downstroke. They concluded that their subjects produced 75% of their weight support during the down-stroke and 25% during the up-stroke. Many earlier studies had assumed (implicitly or explicitly) that lift was generated equally during the two phases of the wingbeat cycle, as is the case of insects of a similar size. This finding shows that hummingbirds' hovering is similar to, but distinct from, that of hovering insects such as the hawk moths.[7]

The Giant Hummingbird's wings beat at 8–10 beats per second, the wings of medium-sized hummingbirds beat about 20–25 beats per second and the smallest can reach 100 beats per second during courtship displays.

Metabolism

File:Hummingbird in ggp 24.JPG
Anna's Hummingbird, Calypte anna performs personal grooming

With the exception of insects, hummingbirds while in flight have the highest metabolism of all animals, a necessity in order to support the rapid beating of their wings. Their heart rate can reach as high as 1,260 beats per minute, a rate once measured in a Blue-throated Hummingbird.[8] They also consume more than their own weight in nectar each day, and to do so they must visit hundreds of flowers daily. Hummingbirds are continuously hours away from starving to death, and are able to store just enough energy to survive overnight.[9]

Hummingbirds are capable of slowing down their metabolism at night, or any other time food is not readily available. They enter a hibernation-like state known as torpor. During torpor, the heart rate and rate of breathing are both slowed dramatically (the heart rate to roughly 50–180 beats per minute), reducing the need for food.

The dynamic range of metabolic rates in hummingbirds (Suarez and Gass 2002) requires a corresponding dynamic range in kidney function (Bakken et al. 2004). The glomerulus is a cluster of capillaries in the nephrons of the kidney which removes certain substances from the blood, like a filtration mechanism. The rate at which blood is processed is called the glomerular filtration rate (GFR). Most often these fluids are reabsorbed by the kidneys. During torpor, to prevent dehydration, the GFR slows, preserving necessities for the body such as glucose, water and salts. GFR also slows when a bird is undergoing water deprivation. The interruption of GFR is a survival and physiological mechanism unique to hummingbirds (Bakken et al. 2004).

Studies of hummingbirds' metabolisms are highly relevant to the question of how a migrating Ruby-throated Hummingbird can cross 800 km (500 mi) of the Gulf of Mexico on a nonstop flight, as field observations suggest it does. This hummingbird, like other birds preparing to migrate, stores up fat to serve as fuel, thereby augmenting its weight by as much as 100 percent and hence increasing the bird's potential flying time.[10]

Lifespan

Hummingbirds have surprisingly long lifespans for organisms with such rapid metabolisms. Though many die during their first year of life, especially in the vulnerable period between hatching and leaving the nest (fledging), those that survive may live a decade or more. Among the better known North American species, average lifespan is 3 to 5 years. By comparison, the smaller shrews, among the smallest of all mammals, seldom live more than 2 years.[11] The longest recorded lifespan in the wild is that of a female Broad-tailed Hummingbird that was banded (ringed) as an adult at least one year old then recaptured 11 years later, making her at least 12 years old. Other longevity records for banded hummingbirds include an estimated minimum age of 10 years 1 month for a female Black-chinned similar in size to Broad-tailed, and at least 11 years 2 months for a much larger Buff-bellied Hummingbird.[12]

Range

Hummingbirds are found natively in the Americas, from southern Alaska to Tierra del Fuego, including the Caribbean. The majority of species occur in tropical and subtropical Central and South America, but several species also breed in temperate areas. Only the migratory Ruby-throated Hummingbird breeds in continental North America east of the Mississippi River and Great Lakes. The Black-chinned Hummingbird, its close relative and another migrant, is the most widespread and common species in the western United States, while the Rufous Hummingbird is the most widespread species in western Canada.[13]

Most hummingbirds of the U.S. and Canada migrate south in fall to spend the winter in northern Mexico or Central America. A few southern South American species also move to the tropics in the southern winter. A few species are year-round residents in the warmer coastal and interior desert regions. Among these is Anna's Hummingbird, a common resident from southern California inland to southern Arizona and north to southwestern British Columbia.

The Rufous Hummingbird is one of several species that breed in western North America and are wintering in increasing numbers in the southeastern United States, rather than in tropical Mexico. Thanks in part to artificial feeders and winter-blooming gardens, hummingbirds formerly considered doomed by faulty navigational instincts are surviving northern winters and even returning to the same gardens year after year. Individuals that survive winters in the north, however, may have altered internal navigation instincts that could be passed on to their offspring. The Rufous Hummingbird nests farther north than any other species and must tolerate temperatures below freezing on its breeding grounds. This cold hardiness enables it to survive temperatures well below freezing, provided that adequate shelter and feeders are available.

Reproduction

Hummingbird nest with two chicks in Santa Monica, California
Calliope Hummingbird feeding two chicks in Grand Teton National Park

As far as is known, male hummingbirds do not take part in nesting. Most species build a cup-shaped nest on the branch of a tree or shrub, though a few tropical species normally attach their nests to leaves. The nest varies in size relative to species, from smaller than half of a walnut shell to several centimeters in diameter. In many hummingbird species, spider silk is used to bind the nest material together and secure the structure to its support. The unique properties of silk allow the nest to expand with the growing young. Two white eggs are laid which, despite being the smallest of all bird eggs, are in fact large relative to the hummingbird's adult size. Incubation lasts 12 to 19 days, depending on species, ambient temperature, and female attentiveness to the nest. Their mother feeds the nestlings on small arthropods and nectar by inserting her bill into the open mouth of a nestling and regurgitating the food into its crop.

Systematics and evolution

Hummingbird feather

Traditionally, hummingbirds are placed in the order Apodiformes, which also contains the swifts, though some taxonomists have separated them into their own order, Trochiliformes. Hummingbirds' wing bones are hollow and fragile, making fossilization difficult and leaving their evolutionary history poorly documented. Though scientists theorize that hummingbirds originated in South America, where there is the greatest species diversity, possible ancestors of extant hummingbirds may have lived in parts of Europe to what is southern Russia today.[citation needed]

There are between 325 and 340 species of hummingbird, depending on taxonomic viewpoint, historically divided into two subfamilies, the hermits (subfamily Phaethornithinae, 34 species in six genera), and the typical hummingbirds (subfamily Trochilinae, all the others). However, recent phylogenetic analyses by McGuire et al. (2007) suggest that this division is slightly inaccurate, and that there are nine major clades of hummingbirds: the Topazes, the Hermits, the Mangoes, the Coquettes, the Brilliants, the Giant Hummingbird (Patagona gigas), the Mountain Gems, the Bees, and the Emeralds. The Topazes (Topaza pella and Florisuga mellivora) have the oldest split with the rest of the hummingbirds. The hummingbirds are the second most diverse bird family on earth (after the tyrant flycatchers).

Fossil hummingbirds are known from the Pleistocene of Brazil and the Bahamas—though neither has yet been scientifically described—and there are fossils and subfossils of a few extant species known; until recently, older fossils had not been securely identifiable as hummingbirds.

In 2004, Dr. Gerald Mayr of the Senckenberg Museum in Frankfurt am Main identified two 30-million-year-old hummingbird fossils and published his results in Nature.[14] The fossils of this primitive hummingbird species, named Eurotrochilus inexpectatus ("unexpected European hummingbird"), had been sitting in a museum drawer in Stuttgart; they had been unearthed in a clay pit at Wiesloch-Frauenweiler, south of Heidelberg, Germany and, because it was assumed that hummingbirds never occurred outside the Americas, were not recognized to be hummingbirds until Mayr took a closer look at them.

Fossils of birds not clearly assignable to either hummingbirds or a related, extinct family, the Jungornithidae, have been found at the Messel pit and in the Caucasus, dating from 40–35 mya; this indicates that the split between these two lineages indeed occurred at that date. The areas where these early fossils have been found had a climate quite similar to the northern Caribbean or southernmost China during that time. The biggest remaining mystery at the present time is what happened to hummingbirds in the roughly 25 million years between the primitive Eurotrochilus and the modern fossils. The astounding morphological adaptations, the decrease in size, and the dispersal to the Americas and extinction in Eurasia all occurred during this timespan. DNA-DNA hybridization results [15] suggest that the main radiation of South American hummingbirds at least partly took place in the Miocene, some 12–13 mya, during the uplifting of the northern Andes.

Lists of species and genera

Feeders and artificial nectar

Hummingbirds will also take sugar water from artificial feeders. Such feeders allow people to observe and enjoy hummingbirds up close while providing the birds with a reliable source of energy, especially when flower blossoms are less abundant.

Hummingbirds will either hover or perch to feed; red feeders are preferred, but colored liquid is not necessary and may be hazardous to their health.
Hummingbird hovering to feed at a red feeder with yellow "flowers"

Only white granulated sugar is proven safe to use in hummingbird feeders. A ratio of 1 cup sugar to 4 cups water is a common recipe.[16] Boiling and then cooling this mixture before use has been recommended to help deter the growth of bacteria and yeasts. Powdered sugars contain corn starch as an anti-caking agent; this additive can contribute to premature fermentation of the solution. Brown, turbinado, and "raw" sugars contain iron, which can be deadly to hummingbirds if consumed over long periods.[17] Honey is made by bees from the nectar of flowers, but it contains sugars that are less palatable to hummingbirds and promotes the growth of microorganisms that may be dangerous to their health.[18][19]

Red food dye is often added to homemade solutions. Commercial products sold as "instant nectar" or "hummingbird food" may also contain preservatives and/or artificial flavors as well as dyes. The long-term effects of these additives on hummingbirds have not been studied, but studies on laboratory animals indicate the potential to cause disease and premature mortality at high consumption rates.[20] Although some commercial products contain small amounts of nutritional additives, hummingbirds obtain all necessary nutrients from the insects they eat. This renders the added nutrients unnecessary.[13]

Other animals also visit hummingbird feeders. Bees, wasps, and ants are attracted to the sugar water and may crawl into the feeder, where they may become trapped and drown. Orioles, woodpeckers, bananaquits, and other larger animals are known to drink from hummingbird feeders, sometimes tipping them and draining the liquid.[21] In the southwestern United States, two species of nectar-drinking bats (Leptonycteris yerbabuenae and Choeronycteris mexicana) visit hummingbird feeders to supplement their natural diet of nectar and pollen from saguaro cacti and agaves.[22]

In myth and culture

Aztecs wore hummingbird talismans, the talismans being representations as well as actual hummingbird fetishes formed from parts of real hummingbirds: emblematic for their vigor, energy and propensity to do work along with their sharp beaks that mimic instruments of weaponry, bloodletting, penetration and intimacy. Hummingbird talismans were prized as drawing sexual potency, energy, vigor and skill at arms and warfare to the wearer.[23]

Aerial photograph of hummingbird image at Nazca in Peru

See also

Notes

  1. ^ Robert S. Ridgely and Paul G. Greenfield, "The Birds of Ecuador volume 2- Field Guide", Cornell University Press, 2001
  2. ^ Clark and Dudley 2009. Flight costs of long, sexually selected tails in hummingbirds. Proceedings of the Royal Society of London B. Published online, Mar 2009.
  3. ^ Rodríguez-Gironés MA, Santamaría L (2004) Why Are So Many Bird Flowers Red? PLoS Biol 2(10): e350 doi:10.1371/journal.pbio.0020350
  4. ^ Altschuler, D. L. 2003. Flower Color, Hummingbird Pollination, and Habitat Irradiance in Four Neotropical Forests. Biotropica 35(3): 344–355.
  5. ^ Nicolson, S. W., and P. A. Fleming. 2003. Nectar as food for birds: the physiological consequences of drinking dilute sugar solutions. Plant Syst. Evol. 238: 139–153 (2003) DOI 10.1007/s00606-003-0276-7
  6. ^ Rayner, J.M.V. 1995. Dynamics of vortex wakes of flying and swimming vertebrates. J. Exp. Biol. 49:131–155.
  7. ^ Warrick, D. R.; Tobalske, B.W. & Powers, D.R. (2005): Aerodynamics of the hovering hummingbird. Nature 435: 1094–1097 doi:10.1038/nature03647 (HTML abstract)
  8. ^ Lanny Chambers. "About Hummingbirds". Hummingbirds.net. Retrieved 25 January 2009.
  9. ^ Hainsworth, Reed (May 1993). "Hummingbird Feeding". Wildbird Magazine. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  10. ^ Skutch, Alexander F. & Singer, Arthur B. (1973): The Life of the Hummingbird. Crown Publishers, New York. ISBN 0-517-50572-X
  11. ^ [Churchfield, Sara. The natural history of shrews. 1990, Christopher Helm, Ltd., London.]
  12. ^ Patuxent Wildlife Research Center, Bird Banding Laboratory. Longevity Records AOU Numbers 3930 - 4920 2009-08-31. Last accessed 2009-09-27.
  13. ^ a b Williamson, S. L. 2002. A Field Guide to Hummingbirds of North America (Peterson Field Guide Series). Houghton Mifflin Co., Boston. ISBN 0-618-02496-4
  14. ^ "Oldest hummingbird fossil found". Cbc.ca. 2004-05-06. Retrieved 2009-01-25.
  15. ^ Bleiweiss, Robert; Kirsch, John A. W. & Matheus, Juan Carlos (1999): DNA-DNA hybridization evidence for subfamily structure among hummingbirds. Auk 111(1): 8–19. Template:PDFlink
  16. ^ Hummingbird Nectar Recipe
  17. ^ Arizona Veterinary Diagnostic Laboratory Newsletter, April 2005
  18. ^ "Feeders and Feeding Hummingbirds (The Entire Article)". Faq.gardenweb.com. 2008-01-09. Retrieved 2009-01-25.
  19. ^ "Hummingbird F.A.Q.s from the Southeastern Arizona Bird Observatory". Sabo.org. 2008-11-25. Retrieved 2009-01-25.
  20. ^ Trochilids.com: Should I Add Red Dye to My Hummingbird Food?
  21. ^ * Williamson, S. 2000. Attracting and Feeding Hummingbirds. (Wild Birds Series) T.F.H. Publications, Neptune City, New Jersey. ISBN 0-7938-3580-1
  22. ^ The Firefly Forest: Tucson's Hummingbird Feeder Bats
  23. ^ Werness, Hope B (2004). The Continuum Encyclopedia of Animal Symbolism in Art. Continuum International Publishing Group. p. 229. Retrieved 2009-01-03. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)

References

Bakken, B. H., McWhorter, T. J., Tsahar, E., Martinez del Rio, C. (2004). Hummingbirds arrest their kidneys at night: diel variation in glomerular filtration rate in Selasphorus platycercus. The Journal of Experimental Biology. 207: 4383-4391.

  • del Hoyo, J.; Elliott, A. & Sargatal, J. (editors) (1999): Handbook of Birds of the World, Volume 5: Barn-owls to Hummingbirds. Lynx Edicions, Barcelona. ISBN 84-87334-25-3
  • Gerwin, John A. & Zink, Robert M. (1998): Phylogenetic patterns in the Trochilidae. Auk 115(1): 105-118. Template:PDFlink
  • McGuire, J. A., Witt, C. C., Altshuler, D. L., and Remsen Jr., J. V. 2007. Phylogenetic systematics and biogography of hummingbirds: Bayesian and maximum likelihood analyses of partitioned data and selection of an appropriate partitioning strategy. Systematic Biology, 56: 837-856.
  • Meyer de Schauensee, Rodolphe (1970): A Guide to Birds of South America. Livingston, Wynnewood, PA.
  • Stiles, Gary. 1981. Geographical Aspects of Bird Flower Coevolution, with Particular Reference to Central America. Annals of the Missouri Botanical Garden 68:323-351.
  • Suarez, R. K., Gass, C. L. (2002). Hummingbirds foraging and the relation between bioenergetics and behavior. Comparative Biochemistry and Physiology Part A. 133: 335-343.
  • Williamson, S. 2000. Attracting and Feeding Hummingbirds. (Wild Birds Series) T.F.H. Publications, Neptune City, New Jersey. ISBN 0-7938-3580-1
  • Williamson, S. L. 2002. A Field Guide to Hummingbirds of North America (Peterson Field Guide Series). Houghton Mifflin Co., Boston. ISBN 0-618-02496-4
Wikimedia Commons has media related to Trochilidae.

Template:Link FA

Retrieved from "https://en.wikipedia.org/w/index.php?title=Hummingbird&oldid=320335617"