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Hummingbirds have the highest metabolism of all vertebrate animals – a necessity to support the rapid beating of their wings during hovering and fast forward flight. [6] [91] During flight and hovering, oxygen consumption per gram of muscle tissue in a hummingbird is about 10 times higher than that measured in elite human athletes. [5] Hummingbirds achieve this extraordinary capacity for oxygen consumption by an exceptional density and proximity of capillaries and mitochondria in their flight muscles. [92] A typical fist-sized model, traditionally made of wood with a blunt iron tip, is meant to be set in motion by briskly pulling a string or rope tightly coiled around the body. The rope is best wound starting near the tip and progressing up along the widening body, so that the tension of the string will remain roughly constant while the top's angular speed increases. Trinidad and Tobago, known as "The land of the hummingbird," displays a hummingbird on that nation's coat of arms, [228] 1-cent coin, [229] and livery on its national airline, Caribbean Airlines. [230]
a b Crabtree, H. (1909). An Elementary Treatment of the Theory of Spinning Tops and Gyroscopic Motion. London: Longman, Green and C. ISBN 9781418179892. Hummingbirds are named for the prominent humming sound their wingbeats make while flying and hovering to feed or interact with other hummingbirds. [71] Humming serves communication purposes by alerting other birds of the arrival of a fellow forager or potential mate. [71] The humming sound derives from aerodynamic forces generated by the downstrokes and upstrokes of the rapid wingbeats, causing oscillations and harmonics that evoke an acoustic quality likened to that of a musical instrument. [71] [72] The humming sound of hummingbirds is unique among flying animals, compared to the whine of mosquitoes, buzz of bees, and "whoosh" of larger birds. [71] [72] Hummingbirds host a highly specialized lice fauna. Two genera of Ricinid lice, Trochiloecetes and Trochiliphagus are specialized on them, often infesting 5-15% of their populations. Contrarily, two genera of Menoponid lice, Myrsidea and Leremenopon are extremely rare on them. [138] Reproduction [ edit ] Video of a hummingbird building a nestBattle Flapper | Bomb Hawk | Cannon Flapper | Egg Bishop | Egg Hammer | Egg Pawn | Egg Pawn Bunny | Egg Pawn Manager (gun) | Egg Pawn Manager (SF gun) | Falco | Flapper | Gun Hunter | Klagen | Knight Pawn | Laser Flapper | Rhino Cannon | Sea Pawn | Solid Pawn Dalsgaard, Bo; Martín González, Ana M.; Olesen, Jens M.; etal. (2009). "Plant-hummingbird interactions in the West Indies: Floral specialisation gradients associated with environment and hummingbird size". Oecologia. 159 (4): 757–766. Bibcode: 2009Oecol.159..757D. doi: 10.1007/s00442-008-1255-z. PMID 19132403. S2CID 35922888. Hummingbird kidneys also have a unique ability to control the levels of electrolytes after consuming nectars with high amounts of sodium and chloride or none, indicating that kidney and glomerular structures must be highly specialized for variations in nectar mineral quality. [111] Morphological studies on Anna's hummingbird kidneys showed adaptations of high capillary density in close proximity to nephrons, allowing for precise regulation of water and electrolytes. [110] [112] Hemoglobin adaptation to altitude [ edit ]
Perception of sweetness in nectar evolved in hummingbirds during their genetic divergence from insectivorous swifts, their closest bird relatives. [197] Although the only known sweet sensory receptor, called T1R2, [198] is absent in birds, receptor expression studies showed that hummingbirds adapted a carbohydrate receptor from the T1R1- T1R3 receptor, identical to the one perceived as umami in humans, essentially repurposing it to function as a nectar sweetness receptor. [197] This adaptation for taste enabled hummingbirds to detect and exploit sweet nectar as an energy source, facilitating their distribution across geographical regions where nectar-bearing flowers are available. [197] Tongue as a micropump [ edit ] Drawing of a hummingbird tongue; 1874, unknown artist. Upon reaching nectar in a flower, the tongue splits into opposing tips fringed with lamellae and grooves, which fill with nectar, then retracts to a cylindrical configuration into the bill to complete the drink. [199] [200] By merely shifting position, feather regions of a muted-looking bird can instantly become fiery red or vivid green. [68] In courtship displays for one example, males of the colorful Anna's hummingbird orient their bodies and feathers toward the sun to enhance the display value of iridescent plumage toward a female of interest. [69] Akatento · Aotento · Ape · Bu-Bu · Buzzer · Clam · Condor · Gaogao · Gekogeko · Ginpe · Guards · Guruguru · Hariisen · Jousun · Juggling · Kamaki · Kyacchaa · Marun · Minimole · Muukaden · Spina · Takkon · Uutsubo · Yadokk · Yukigasen
Sexual size and bill differences likely evolved due to constraints imposed by courtship, because mating displays of male hummingbirds require complex aerial maneuvers. [63] Males tend to be smaller than females, allowing conservation of energy to forage competitively and participate more frequently in courtship. [63] Thus, sexual selection favors smaller male hummingbirds. [63] Maglianesi, M.A.; Blüthgen, N.; Böhning-Gaese, K. & Schleuning, M. (2014). "Morphological traits determine specialization and resource use in plant–hummingbird networks in the Neotropics". Ecology. 95 (12): 3325–334. doi: 10.1890/13-2261.1.
