Editing Hummingbird (section)

== Feeding ==
[[File:Humming birds feeding at 1500fps.webm|thumb|Hummingbirds feeding; video recorded at 1,500 frames per second]]
[[File:Hummingbird.ogg|thumb|Hummingbird visiting flowers in [[Copiapó, Chile]]: The apparent slow movement of hummingbird wings is a result of the [[stroboscopic effect]].]]
[[File:Hummmingbird at honeybee haven.webm|thumb|thumbtime=30|[[Calypte anna|Anna’s hummingbird]] on [[Salvia]]]]

All hummingbirds are overwhelmingly [[nectarivorous]],<ref name="eb-h"/><ref name="hoya">{{cite book |last1=del Hoyo |first1=Josep |last2=Andrew |first2=Elliott |last3=Sargatal |first3=Jordi |title=Handbook of the Birds of the World Vol. 5. Barn-owls to Hummingbirds |date=1999 |publisher=Lynx Edicions |location=Barcelona |isbn=84-87334-25-3 |pages=475–680}}</ref><ref name="hermits">{{cite journal | last=Stiles | first=F. Gary | title=Behavioral, Ecological and Morphological Correlates of Foraging for Arthropods by the Hummingbirds of a Tropical Wet Forest | journal=The Condor | publisher=Oxford University Press (OUP) | volume=97 | issue=4 | year=1995 | url=https://academic.oup.com/condor/article-abstract/97/4/853/5126159 | doi=10.2307/1369527 | pages=853–878| jstor=1369527 | url-access=subscription }}</ref><ref name="diversity">{{cite journal | last1=Abrahamczyk | first1=Stefan | last2=Kessler | first2=Michael | title=Hummingbird diversity, food niche characters, and assemblage composition along a latitudinal precipitation gradient in the Bolivian lowlands | journal=Journal of Ornithology | publisher=Springer Science and Business Media LLC | volume=151 | issue=3 | date=12 February 2010 | url=https://link.springer.com/article/10.1007/s10336-010-0496-x | doi=10.1007/s10336-010-0496-x | pages=615–625| bibcode=2010JOrni.151..615A | s2cid=25235280 }}</ref><ref name="honey">{{cite journal | last=PYKE | first=GRAHAM H. | title=The foraging behaviour of Australian honeyeaters: a review and some comparisons with hummingbirds | journal=Austral Ecology | publisher=Wiley | volume=5 | issue=4 | year=1980 | url=https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1442-9993.1980.tb01258.x | doi=10.1111/j.1442-9993.1980.tb01258.x | pages=343–369| bibcode=1980AusEc...5..343P | url-access=subscription }}</ref><ref name="cali"/> being by far the most specialized such feeders among birds, as well as the only birds for whom nectar typically comprises the vast majority of energy intake. Hummingbirds exhibit numerous and extensive adaptations to nectarivory, including long, probing bills and tongues which rapidly take up fluids. Hummingbirds also possess the most sophisticated [[Bird flight#Hovering|hovering]] flight of all birds, a necessity for rapidly visiting many flowers without perching. Their [[intestines]] are capable of extracting over 99% of the glucose from nectar feedings within minutes, owing to high densities of glucose transporters (the highest known among vertebrates).<ref name="hoya"/>

As among the most important vertebrate [[pollinator]]s, hummingbirds have [[Coevolution#Birds and bird-pollinated flowers|coevolved]] in complex ways with flowering plants; thousands of [[New World]] species have evolved to be pollinated exclusively by hummingbirds, even barring access to [[insect]] pollinators.<ref name="hoya"/><ref name="hermits"/> In some plants these mechanisms, which include highly modified [[Corolla (flower)|corolla]]s, even render their [[nectaries]] inaccessible to all but certain hummingbirds, i.e., those possessing appropriate beak morphologies (although some hummingbirds rob nectar to overcome this). Bird-pollinated plants (also termed "ornithophilous") were formerly thought to exemplify very close mutualisms, with specific flowering plants coevolving alongside specific hummingbirds in mutualistic pairings. Both ornithophilous plants and hummingbirds are now known to not be nearly selective enough for this to be true.<ref name="hoya"/><ref name="diversity"/><ref name="cali">{{cite journal | last1=Spence | first1=Austin R | last2=Wilson Rankin | first2=Erin E | last3=Tingley | first3=Morgan W | title=DNA metabarcoding reveals broadly overlapping diets in three sympatric North American hummingbirds | journal=Ornithology | publisher=Oxford University Press (OUP) | volume=139 | issue=1 | date=3 December 2021 | url=https://academic.oup.com/auk/article/139/1/ukab074/6429138 | doi=10.1093/ornithology/ukab074 | page=| doi-access=free }}</ref> Less accessible ornithophiles (for example, those requiring long bills) still rely on multiple hummingbird species for pollination. More importantly, hummingbirds tend not to be especially selective nectar-feeders, even regularly visiting non-ornithophilous plants, as well as ornithophiles which appear poorly suited for feeding by their species. Feeding efficiency is optimized, however, when birds feed on flowers better suited to their bill morphologies.<ref name="hoya"/><ref name="hermits"/>

Although they may not be one-to-one, there are still marked overall preferences for certain genera, families, and orders of flowering plants by hummingbirds in general, as well as by certain species of hummingbird. Flowers which are attractive to hummingbirds are often colorful (particularly red), open diurnally, and produce nectar with a high sucrose content; in ornithophilous plants, the corollas are often elongated and tubular, and they may be scentless (several of these are adaptations discouraging insect visitation).<ref name="hoya"/> Some common genera consumed by many species include ''[[Castilleja]]'', ''[[Centropogon]]'', ''[[Costus]]'', ''[[Delphinium]]'', ''[[Heliconia]]'', ''[[Hibiscus]]'', ''[[Inga]]'', and ''[[Mimulus]]''; some of these are primarily insect-pollinated. Three Californian species were found to feed from 62 plant families in 30 orders, with the most frequently occurring orders being [[Apiales]], [[Fabales]], [[Lamiales]], and [[Rosales]]. A hummingbird may have to visit one or two thousand flowers daily to meet energy demands.<ref name="hoya"/><ref name="cali"/><ref name="saopaulo">{{cite journal | last1=Toledo | first1=MCB. | last2=Moreira | first2=DM. | title=Analysis of the feeding habits of the swallow-tailed hummingbird, Eupetomena macroura (Gmelin, 1788), in an urban park in southeastern Brazil | journal=Brazilian Journal of Biology | publisher=FapUNIFESP (SciELO) | volume=68 | issue=2 | year=2008 | doi=10.1590/s1519-69842008000200027 | pages=419–426| pmid=18660974 | doi-access=free }}</ref>

[[File:Green-crowned_brilliant_%26_Heliconia_stricta.jpg|thumb|''Heliconia'' species are popular nectar sources for many hummingbirds; here, a [[green-crowned brilliant]] (''Heliodoxa jacula'') visits ''[[Heliconia stricta]]'']]

Although a high-quality source of energy, nectar is deficient in many [[Macronutrient|macro]]- and [[micronutrient]]s;<ref name="hoya"/><ref name="hermits"/><ref name="protein">{{cite journal | last1=Brice | first1=Ann T. | last2=Grau | first2=C. Richard | title=Protein Requirements of Costa's Hummingbirds Calypte costae | journal=Physiological Zoology | publisher=University of Chicago Press | volume=64 | issue=2 | year=1991 | url=https://www.journals.uchicago.edu/doi/abs/10.1086/physzool.64.2.30158193 | doi=10.1086/physzool.64.2.30158193 | pages=611–626| s2cid=87673164 | url-access=subscription }}</ref> it tends to be low in [[lipid]]s, and although it may contain trace quantities of [[amino acid]]s, some essential acids are severely or entirely lacking. Though hummingbird protein requirements appear to be quite small, at 1.5% of the diet, nectar is still an inadequate source;<ref name="protein"/> most if not all hummingbirds therefore supplement their diet with the consumption of invertebrates.<ref name="hoya"/><ref name="cali"/><ref name="protein"/><ref name="jaw">{{Cite journal |last1=Yanega |first1=Gregor M. |last2=Rubega |first2=Margaret A. |year=2004 |title=Feeding mechanisms: Hummingbird jaw bends to aid insect capture |journal=Nature |volume=428 |issue=6983 |page=615 |bibcode=2004Natur.428..615Y |doi=10.1038/428615a |pmid=15071586 |s2cid=4423676|doi-access=free }}</ref> Insectivory is not thought to be calorically important; nonetheless, regular consumption of arthropods is considered crucial for birds to thrive. In fact, it has been suggested that the majority of non-caloric nutritional needs of hummingbirds are met by insectivory, but nectars do contain appreciable quantities of certain [[vitamin]]s and [[mineral]]s.<ref>{{cite journal | last1=Carroll | first1=Scott P. | last2=Moore | first2=Laurel | title=Hummingbirds take their vitamins | journal=Animal Behaviour | publisher=Elsevier BV | volume=46 | issue=4 | year=1993 | url=https://www.sciencedirect.com/science/article/abs/pii/S0003347283712613 | doi=10.1006/anbe.1993.1261 | pages=817–820| s2cid=54417626 | url-access=subscription }}</ref> (Here, "[[insectivory]]" refers to the consumption of any arthropod, not exclusively insects).

Though not as insectivorous as once believed, and far less so than most of their relatives and ancestors among the [[Strisores]] (e.g., swifts), insectivory is probably of regular importance to most hummingbirds. About 95% of individuals from 140 species in one study showed evidence of arthropod consumption,<ref name="protein"/> while another study found arthropod remains in 79% of over 1600 birds from sites across South and Central America.<ref name="dominica">{{cite journal | last1=Chavez-Ramirez | first1=Felipe | last2=Dowd | first2=McAlister | title=Arthropod Feeding by Two Dominican Hummingbird Species | journal=The Wilson Bulletin | publisher=Wilson Ornithological Society | volume=104 | issue=4 | year=1992 | jstor=4163229 | pages=743–747 | url=http://www.jstor.org/stable/4163229 | access-date=2 September 2023}}</ref> Some species have even been recorded to be largely or entirely insectivorous for periods of time, particularly when nectar sources are scarce, and possibly, for some species, with seasonal regularity in areas with a [[wet season]]. Observations of seasonal, near-exclusive insectivory have been made for [[Blue-throated mountaingem|blue-throated hummingbirds]],<ref name="texas">{{cite journal | last1=Kuban | first1=Joseph F. | last2=Neill | first2=Robert L. | title=Feeding Ecology of Hummingbirds in the Highlands of the Chisos Mountains, Texas | journal=The Condor | publisher=Oxford University Press (OUP) | volume=82 | issue=2 | year=1980 | url=https://academic.oup.com/condor/article-abstract/82/2/180/5204713 | doi=10.2307/1367475 | page=180| jstor=1367475 | url-access=subscription }}</ref> as well as [[swallow-tailed hummingbird]]s in an urban park in Brazil.<ref name="saopaulo"/> In Arizona, when nearby nectar sources were seemingly absent, a nesting female broad-tailed hummingbird was recorded feeding only on arthropods for two weeks.<ref name="arizona">{{cite journal | last1=Montgomerie | first1=Robert D. | last2=Redsell | first2=Catherine A. | title=A Nesting Hummingbird Feeding Solely on Arthropods | journal=The Condor | publisher=Oxford University Press (OUP) | volume=82 | issue=4 | year=1980 | url=https://sora.unm.edu/sites/default/files/journals/condor/v082n04/p0463-p0464.pdf | doi=10.2307/1367577 | page=463| jstor=1367577 }}</ref> Other studies report 70–100% of feeding time devoted to arthropods;<ref name="saopaulo"/><ref name="dominica"/> these accounts suggest a degree of adaptability, particularly when appropriate nectar sources are unavailable, although nectarivory always predominates when flowers are abundant (e.g., in non-seasonal tropical habitats). In addition, the aforementioned Arizona study only surveyed a small portion of the study area, and mostly did not observe the bird while she was off the nest. Similar concerns have been raised for other reports, leading to skepticism over whether hummingbirds can in fact subsist without nectar for extended periods at all.<ref name="hermits"/>

[[File:Chironomus plumosus01.jpg|thumb|Among the commonest invertebrate food items of hummingbirds are flies, particularly [[Chironomidae|nonbiting midges]], members of the family Chironomidae]]

Hummingbirds exhibit various feeding strategies and some morphological adaptations for insectivory.<ref name="jaw"/> Typically, they [[Hawking (birds)|hawk]] for small flying insects, but also glean [[spider]]s from their [[Spiderweb|web]]s.<ref name="hoya"/><ref name="hermits"/> Bill shape may play a role, as hummingbirds with longer or more curved bills may be unable to hawk efficiently, and so rely more heavily on gleaning spiders.<ref name="cali"/> Regardless of bill shape, spiders are a common [[prey]] item; other very common prey items include [[flies]], especially those of the family [[Chironomidae]], as well as various [[Hymenoptera]]ns (such as [[wasp]]s and [[ant]]s) and [[Hemiptera]]ns.<ref name="hoya"/><ref name="cali"/><ref name="hermits"/> The aforementioned California study found three species to consume invertebrates from 72 families in 15 orders, with flies alone occurring in over 90% of samples; the three species exhibited high dietary overlap, with little evidence for [[niche partitioning]].<ref name="cali"/> This suggests that prey availability is not a limiting resource for hummingbirds.

Estimates of overall dietary makeup for hummingbirds vary, but insectivory is often cited as comprising 5–15% of feeding time budgets, typically;<ref name="hoya"/><ref name="hermits"/><ref name="arizona"/> 2–12% is a figure that is also cited.<ref name="saopaulo"/><ref name="protein"/> In one study, 84% of feeding time was allotted to nectar feeding if breeding females are included, and 89% otherwise; 86% of total feeding records were on nectar.<ref name="honey"/><ref name="arizona"/> It has been estimated, based on time budgets and other data, that the hummingbird diet is generally about 90% nectar and 10% arthropods by mass.<ref name="hoya"/><ref>{{cite journal | last1=Weathers | first1=Wesley W. | last2=Stiles | first2=F. Gary | title=Energetics and Water Balance in Free-Living Tropical Hummingbirds | journal=The Condor | publisher=Oxford University Press (OUP) | volume=91 | issue=2 | year=1989 | url=https://academic.oup.com/condor/article-abstract/91/2/324/5189260 | doi=10.2307/1368310 | page=324| jstor=1368310 | url-access=subscription }}</ref>  As their [[nestlings]] consume only arthropods, and possibly because their own requirements increase, breeding females spend 3–4 times as long as males foraging for arthropods, although 65–70% of their feeding time is still devoted to nectar.<ref name="hermits"/> Estimates for overall insectivory can be as low as <5%. Such low numbers have been documented for some species; insects comprised 3% of foraging attempts for Peruvian [[shining sunbeam]]s in one study,<ref>{{cite journal | last1=Céspedes | first1=Laura N. | last2=Pavan | first2=Lucas I. | last3=Hazlehurst | first3=Jenny A. | last4=Jankowski | first4=Jill E. | title=The behavior and diet of the Shining Sunbeam (''Aglaeactis cupripennis''): A territorial high-elevation hummingbird | journal=The Wilson Journal of Ornithology | publisher=Wilson Ornithological Society | volume=131 | issue=1 | date=9 April 2019 | url=https://meridian.allenpress.com/wjo/article-abstract/131/1/24/430191/The-behavior-and-diet-of-the-Shining-Sunbeam | doi=10.1676/18-79 | page=24| s2cid=91263467 | url-access=subscription }}</ref> while the [[purple-throated carib]] has been reported to spend <1% of time consuming insects in [[Dominica]].<ref name="dominica"/> Both species also have more typical numbers recorded elsewhere, however. Overall, for most hummingbirds, insectivory is an essential and regular, albeit minor, component of the diet, while nectar is the primary feeding focus when conditions allow.<ref name="hoya"/><ref name="dominica"/> It has been shown that floral abundance (but not floral diversity) influences hummingbird diversity, but that arthropod abundance does not (i.e., that it is non-limiting).<ref name="diversity"/><ref name="cali"/>

Hummingbirds do not spend all day flying, as the energy cost would be prohibitive; the majority of their activity consists simply of sitting or perching. Hummingbirds eat many small meals and consume around half their weight in nectar (twice their weight in nectar, if the nectar is 25% sugar) each day.<ref>{{Cite book |last=Unwin |first=Mike |url=https://books.google.com/books?id=Szh7ENErBUAC&q=hummingbird+twelve+times+their+own+body+weight+in+nectar&pg=PA57 |title=The Atlas of Birds: Diversity, Behavior, and Conservation |publisher=Princeton University Press |year=2011 |isbn=978-1-4008-3825-7 |page=57}}</ref> Hummingbirds digest their food rapidly due to their small size and high metabolism; a mean retention time less than an hour has been reported.<ref>{{Cite book |last1=Stevens |first1=C. Edward |url=https://books.google.com/books?id=DZuAsci2apAC&q=hummingbird+transit+time+1+hour&pg=PA126 |title=Comparative Physiology of the Vertebrate Digestive System |last2=Hume |first2=Ian D. |publisher=Cambridge University Press |year=2004 |isbn=978-0-521-61714-7 |page=126}}</ref> Hummingbirds spend an average of 20% of their time feeding and 75–80% sitting and digesting.<ref name="jmd">{{cite journal  |last1=Diamond |first1=Jared M. |last2=Karasov |first2=William H. |last3=Phan |first3=Duong |last4=Carpenter |first4=F. Lynn |title=Digestive physiology is a determinant of foraging bout frequency in hummingbirds |journal=Nature |volume=320 |issue=6057 |pages=62–3 |date=1986 |pmid=3951548 |doi=10.1038/320062a0 |bibcode=1986Natur.320...62D |s2cid=4363635 |url=https://www.nature.com/articles/320062a0|url-access=subscription }}</ref>

Because their high metabolism makes them vulnerable to [[starvation]], hummingbirds are highly attuned to food sources. Some species, including many found in North America, are territorial and try to guard food sources (such as a feeder) against other hummingbirds, attempting to ensure a future food supply.<ref name=abc/> Additionally, hummingbirds have an enlarged [[hippocampus]], a brain region facilitating spatial memory used to map flowers previously visited during nectar foraging.<ref>{{Cite journal |last1=Ward |first1=B.J. |last2=Day |first2=L.B. |last3=Wilkening |first3=S.R. |last4=Wylie |first4=D.R. |last5=Saucier |first5=D.M. |last6=Iwaniuk |first6=A.N. |display-authors=3 |year=2012 |title=Hummingbirds have a greatly enlarged hippocampal formation |journal=Biology Letters |volume=8 |issue=4 |pages=657–659 |doi=10.1098/rsbl.2011.1180 |pmc=3391440 |pmid=22357941}}</ref>

===Beak specializations===
{{multiple image
|image1=Eutoxeres aquila 28748616.jpg
|width1=175
|caption1=Curved beak (approx. 90<sup>o</sup>) of the [[white-tipped sicklebill]]
|image2=Centropogon grandidentatus (9349553006).jpg
|width2=150
|caption2=[[Centropogon]] flowers
|footer=Coevolution of the sicklebill beak curve facilitates both nectar feeding and pollination of long tubular Centropogon flowers.<ref name=boehm/>
}}

The shapes of hummingbird [[beak]]s (also called bills) vary widely as an adaptation for specialized feeding,<ref name=Berns2012/><ref name=Temeles2010/> with some 7000 flowering plants pollinated by hummingbird nectar feeding.<ref name="leim">{{cite journal |last1=Leimberger|first1=K.G.|last2= Dalsgaard|first2=B.|last3=Tobias|first3=J.A.|last4= Wolf|first4=C.|last5= Betts|first5=M.G. |title=The evolution, ecology, and conservation of hummingbirds and their interactions with flowering plants |journal=Biological Reviews of the Cambridge Philosophical Society |volume=97 |issue=3 |pages=923–959 |date=June 2022 |pmid=35029017 |doi=10.1111/brv.12828|hdl=10044/1/94632 |s2cid=245971244 |hdl-access=free}}</ref> Hummingbird beak lengths range from about {{convert|6|mm|in}} to as long as {{convert|110|mm|in}}.<ref name="morph">{{cite journal |last1=Rico-Guevara |first1=A.|last2= Rubega|first2=M.A.|last3=Hurme|first3=K.J.|last4=Dudley|first4=R. |title=Shifting paradigms in the mechanics of nectar extraction and hummingbird bill morphology |journal=Integrative Organismal Biology|volume=1 |issue=1 |pages=oby006 |date=2019 |pmid=33791513 |pmc=7671138 |doi=10.1093/iob/oby006}}</ref> When catching insects in flight, a hummingbird's jaw [[bending|flexes]] downward to widen the beak for successful capture.<ref name="jaw"/>

The extreme curved beaks of sicklebills are adapted for extracting nectar from the curved corolla tubes of ''Centropogon'' flowers.<ref name="boehm">{{cite journal |last1=Boehm|first1=M.M.A.|last2=Guevara-Apaza |first2=D.|last3= Jankowski|first3=J.E.|last4=Cronk|first4=Q.C.B.|title=Floral phenology of an Andean bellflower and pollination by buff-tailed sicklebill hummingbird |journal=Ecology and Evolution |volume=12 |issue=6 |pages=e8988 |date=July 2022 |pmid=35784085 |pmc=9168340 |doi=10.1002/ece3.8988|bibcode=2022EcoEv..12E8988B }}</ref> Some species, such as hermits (''Phaethornis'' spp.), have long beaks that enable insertion deeply into flowers with long corolla tubes.<ref name=leim/><ref name="betts">{{cite journal |last1=Betts|first1=M.G.|last2= Hadley|first2=A.S.|last3= Kress|first3=W.J. |title=Pollinator recognition by a keystone tropical plant |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=112 |issue=11 |pages=3433–8 |date=March 2015 |pmid=25733902 |pmc=4371984 |doi=10.1073/pnas.1419522112 |bibcode=2015PNAS..112.3433B |doi-access=free }}</ref> [[Chalcostigma|Thornbills]] have short, sharp beaks adapted for feeding from flowers with short corolla tubes and piercing the bases of longer ones. The beak of the [[fiery-tailed awlbill]] has an upturned tip adapted for feeding on nectar from tubular flowers while hovering.<ref>{{cite web |title=Fiery-tailed awlbills |url=https://beautyofbirds.com/fierytailedawlbillhummingbirds/ |publisher=Beauty of Birds |access-date=8 March 2023 |date=16 September 2021}}</ref>

=== Perception of sweet nectar ===

Perception of sweetness in nectar evolved in hummingbirds during their [[genetic divergence]] from insectivorous swifts, their closest bird relatives.<ref name="baldwin">{{Cite journal |last1=Baldwin |first1=Maude W. |last2=Toda |first2=Yasuka |last3=Nakagita |first3=Tomoya |last4=O'Connell |first4=Mary J. |last5=Klasing |first5=Kirk C. |last6=Misaka |first6=Takumi |last7=Edwards |first7=Scott V. |last8=Liberles |first8=Stephen D. |year=2014 |title=Sensory biology. Evolution of sweet taste perception in hummingbirds by transformation of the ancestral umami receptor |journal=Science |volume=345 |issue=6199 |pages=929–933 |bibcode=2014Sci...345..929B |doi=10.1126/science.1255097 |pmc=4302410 |pmid=25146290}}</ref> Although the only known sweet sensory receptor, called [[TAS1R2|T1R2]],<ref>{{Cite journal |last=Li|first=X. |year=2009 |title=T1R receptors mediate mammalian sweet and umami taste |journal=American Journal of Clinical Nutrition |volume=90 |issue=3 |pages=733S–37S |doi=10.3945/ajcn.2009.27462G |pmid=19656838 |doi-access=free}}</ref> is absent in birds, receptor expression studies showed that hummingbirds adapted a carbohydrate receptor from the [[TAS1R1|T1R1]]-[[TAS1R3|T1R3]] receptor, identical to the one perceived as [[umami]] in humans, essentially repurposing it to function as a nectar sweetness receptor.<ref name="baldwin"/> 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.<ref name="baldwin"/>

=== Tongue as a micropump ===
[[File:PSM V05 D295 Hummingbird tongue.jpg|thumb|Drawing of a hummingbird tongue; 1874, unknown artist. Upon reaching nectar in a flower, the tongue splits into opposing tips fringed with [[Lamella (cell biology)|lamellae]] and grooves, which fill with nectar, then retracts to a cylindrical configuration into the bill to complete the drink.<ref name=rico/><ref name=frank/>]]

Hummingbirds drink with their long tongues by rapidly lapping nectar. Their tongues have [[Semicircle|semicircular]] tubes which run down their lengths to facilitate nectar consumption via rapid pumping in and out of the nectar.<ref name="rico">{{Cite journal |last1=Rico-Guevara |first1=Alejandro |last2=Fan |first2=Tai-Hsi |last3=Rubega |first3=Margaret A. |date=2015-08-22 |title=Hummingbird tongues are elastic micropumps |journal=Proceedings of the Royal Society B |volume=282 |issue=1813 |pages=20151014 |doi=10.1098/rspb.2015.1014 |issn=0962-8452 |pmc=4632618 |pmid=26290074}}</ref><ref name="frank">{{Cite news |last1=Frank |first1=David |last2=Gorman |first2=James |date=2015-09-08 |title=ScienceTake {{!}} The hummingbird's tongue |work=The New York Times |url=https://www.nytimes.com/video/science/100000003892113/the-hummingbirds-tongue.html |access-date=2015-09-10 |issn=0362-4331}}</ref> While capillary action was believed to be what drew nectar into these tubes,<ref name=kim/> high-speed photography revealed that the tubes open down their sides as the tongue goes into the nectar, and then close around the nectar, trapping it so it can be pulled back into the beak over a period of 14 [[millisecond]]s per lick at a rate of up to 20 licks per second.<ref>{{Cite journal |last1=Rico-Guevara |first1=A. |last2=Rubega |first2=M.A. |year=2011 |title=The hummingbird tongue is a fluid trap, not a capillary tube |journal=Proceedings of the National Academy of Sciences |volume=108 |issue=23 |pages=9356–360 |bibcode=2011PNAS..108.9356R |doi=10.1073/pnas.1016944108 |pmc=3111265 |pmid=21536916 |doi-access=free}}</ref><ref name="cade1">{{Cite web |last=Mosher|first=D. |date=2 May 2011 |title=High-speed video shows how hummingbirds really drink |url=https://www.wired.com/wiredscience/2011/05/hummingbird-tongue-drinking |access-date=13 August 2022 |publisher=Wired}}</ref> The tongue, which is forked, is compressed until it reaches nectar, then the tongue springs open, the rapid action traps the nectar which moves up the grooves, like a [[pump]] action, with [[capillary action]] not involved.<ref name="rico"/><ref name=frank/><ref name=cade1/><ref>{{Cite news |last=Gorman |first=James |date=2015-09-08 |title=The hummingbird's tongue: How it works |work=The New York Times |url=https://www.nytimes.com/2015/09/08/science/the-hummingbirds-tongue-how-it-works.html |access-date=2015-09-10 |issn=0362-4331}}</ref> Consequently, tongue flexibility enables accessing, transporting and unloading nectar via pump action,<ref name="rico"/><ref name=frank/> not by a capillary [[syphon]] as once believed.<ref name="kim">{{Cite journal |last1=Kim |first1=W. |last2=Peaudecerf |first2=F. |last3=Baldwin |first3=M.W. |last4=Bush |first4=J.W. |year=2012 |title=The hummingbird's tongue: A self-assembling capillary syphon |journal=Proceedings of the Royal Society B: Biological Sciences |volume=279 |issue=1749 |pages=4990–996 |doi=10.1098/rspb.2012.1837 |pmc=3497234 |pmid=23075839}}</ref>

[[File:Ruby-Throated Hummingbird.png|thumb|upright|Male [[ruby-throated hummingbird]] (''Archilochus colubris'') with tongue extended]]

=== Feeders and artificial nectar ===
[[File:Hummingbirds at feeder.jpg|thumb|Hummingbirds hovering at an artificial nectar feeder]]

In the wild, hummingbirds visit flowers for food, extracting nectar, which is 55% sucrose, 24% glucose, and 21% fructose on a dry-matter basis.<ref>{{Cite journal |last1=Stahl |first1=J.M. |last2=Nepi |first2=M. |last3=Galetto |first3=L. |last4=Guimarães |first4=E. |last5=Machado |first5=S.R. |year=2012 |title=Functional aspects of floral nectar secretion of Ananas ananassoides, an ornithophilous bromeliad from the Brazilian savanna |journal=Annals of Botany |volume=109 |issue=7 |pages=1243–252 |doi=10.1093/aob/mcs053 |pmc=3359915 |pmid=22455992}}</ref> Hummingbirds also take sugar-water from [[bird feeder]]s, which 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. A negative aspect of artificial feeders, however, is that the birds may seek less flower nectar for food, and so may reduce the amount of pollination their feeding naturally provides.<ref>{{Cite journal |last1=Avalos |first1=G. |last2=Soto |first2=A. |last3=Alfaro |first3=W. |year=2012 |title=Effect of artificial feeders on pollen loads of the hummingbirds of Cerro de la Muerte, Costa Rica |journal=Revista de Biología Tropical |volume=60 |issue=1 |pages=65–73 |doi=10.15517/rbt.v60i1.2362 |pmid=22458209 |doi-access=free}}</ref>

White granulated sugar is used in hummingbird feeders in a 20% concentration as a common recipe,<ref>{{Cite web |title=Hummingbird Nectar Recipe |date=22 February 2017 |url=https://nationalzoo.si.edu/migratory-birds/hummingbird-nectar-recipe|access-date=2022-09-07 |publisher=Nationalzoo.si.edu}}</ref> although hummingbirds will defend feeders more aggressively when sugar content is at 35%, indicating preference for nectar with higher sugar content.<ref>{{Cite journal |last1=Rousseu |first1=F. |last2=Charette |first2=Y. |last3=Bélisle |first3=M. |year=2014 |title=Resource defense and monopolization in a marked population of ruby-throated hummingbirds (Archilochus colubris) |journal=Ecology and Evolution |volume=4 |issue=6 |pages=776–793 |doi=10.1002/ece3.972 |pmc=3967903 |pmid=24683460|bibcode=2014EcoEv...4..776R }}</ref> Organic and "raw" sugars contain [[iron]], which can be harmful,<ref name="audubon--nectar">{{Cite web |date=14 April 2016 |title=How to Make Hummingbird Nectar |url=http://www.audubon.org/news/how-make-hummingbird-nectar |website=Audubon.com |publisher=Audubon Society |language=en}}</ref> and brown sugar, [[agave syrup]], [[molasses]], and [[Sugar substitute|artificial sweeteners]] also should not be used.<ref name="kern--feeding">{{Cite web |title=Feeding Hummingbirds |url=http://www.kern.audubon.org/hummer_feeding.htm |website=www.kern.audubon.org |publisher=Audubon California Kern River Preserve |access-date=6 April 2017 |archive-date=8 April 2022 |archive-url=https://web.archive.org/web/20220408140247/http://www.kern.audubon.org/hummer_feeding.htm |url-status=dead }}</ref> [[Honey]] is made by bees from the nectar of flowers, but it is not good to use in feeders because when it is diluted with water, [[microorganism]]s easily grow in it, causing it to spoil rapidly.<ref>{{Cite web |date=2008-01-09 |title=Feeders and Feeding Hummingbirds |url=http://faq.gardenweb.com/faq/lists/hummingbird/2003021845028716.html |access-date=2009-01-25 |publisher=Faq.gardenweb.com}}</ref><ref>{{Cite web |date=2008-11-25 |title=Hummingbird F.A.Q.s from the Southeastern Arizona Bird Observatory |url=http://www.sabo.org/hbfaqs.htm#honey |url-status=dead |archive-url=https://web.archive.org/web/20141102002928/http://sabo.org/hbfaqs.htm#honey |archive-date=2014-11-02 |access-date=2009-01-25 |publisher=Sabo.org}}</ref><ref>[http://mdc.mo.gov/discover-nature/outdoor-recreation/nature-viewing/birding/ruby-throated-hummingbirds Attracting Hummingbirds |Missouri Department of Conservation] {{Webarchive|url=https://web.archive.org/web/20120419094054/http://mdc.mo.gov/discover-nature/outdoor-recreation/nature-viewing/birding/ruby-throated-hummingbirds |date=19 April 2012 }} Retrieved on 2013-04-01</ref>

[[Allura Red AC|Red food dye]] was once thought to be a favorable ingredient for the nectar in home feeders, but it is unnecessary.<ref name="dye">{{Cite web |last=Chambers |first=Lanny |date=2016 |title=Please Don't Use Red Dye |url=http://www.hummingbirds.net/dye.html |access-date=25 June 2016 |publisher=Hummingbirds.net}}</ref> Commercial products sold as "instant nectar" or "hummingbird food" may also contain [[preservative]]s or artificial flavors, as well as dyes, which are unnecessary and potentially harmful.<ref name="dye"/><ref>{{Cite web |title=Should I Add Red Dye to My Hummingbird Food? |url=http://www.trochilids.com/dye.html |access-date= 20 March 2010 |publisher=Trochilids.com}}</ref> Although some commercial products contain small amounts of nutritional additives, hummingbirds obtain all necessary nutrients from the insects they eat, rendering added nutrients unnecessary.<ref name="hummingbirds2002">{{cite book |last=Williamson |first=S. L. |title=A Field Guide to Hummingbirds of North America |series=Peterson Field Guide Series |publisher=Houghton Mifflin |location=Boston |year=2002 |isbn=0-618-02496-4}}</ref>

===Visual cues of foraging===

Hummingbirds have exceptional visual acuity providing them with discrimination of food sources while foraging.<ref name=lisney/> Although hummingbirds are thought to be attracted to color while seeking food, such as red flowers or artificial feeders, experiments indicate that location and flower nectar quality are the most important "[[beacon]]s" for foraging.<ref name="audubon">{{Cite web |date=28 May 2013 |title=Hummingbirds See Red |url=http://www.audubon.org/news/hummingbirds-see-red |access-date=23 April 2017 |publisher=US National Audubon Society}}</ref><ref>{{Cite web |date=16 March 2012 |title=Hummingbirds take no notice of flower color |url=https://phys.org/news/2012-03-hummingbirds.html |access-date=22 April 2017 |publisher=Phys.org}}</ref> Hummingbirds depend little on visual cues of flower color to beacon to nectar-rich locations, but rather they use surrounding landmarks to find the nectar reward.<ref>{{Cite journal |last1=Hurly |first1=T.A. |last2=Franz |first2=S |last3=Healy |first3=S.D. |year=2010 |title=Do rufous hummingbirds (''Selasphorus rufus'') use visual beacons? |journal=Animal Cognition |volume=13 |issue=2 |pages=377–383 |doi=10.1007/s10071-009-0280-6 |pmid=19768647 |s2cid=9189780}}</ref><ref>{{Cite journal |last1=Hurly |first1=T.A. |last2=Fox |first2=T.A.O. |last3=Zwueste |first3=D.M. |last4=Healy |first4=S.D. |year=2014 |title=Wild hummingbirds rely on landmarks not geometry when learning an array of flowers |url=https://research-repository.st-andrews.ac.uk/bitstream/10023/6422/1/Hurly_et_al_Anim_Cog_14.pdf |journal=Animal Cognition |volume=17 |issue=5 |pages=1157–165 |doi=10.1007/s10071-014-0748-x |pmid=24691650 |hdl-access=free |hdl=10023/6422 |s2cid=15169177}}</ref><ref name="Hornsby">{{cite journal |last1=Hornsby |first1=Mark A.W. |last2=Healy |first2=Susan D. |last3=Hurly |first3=T. Andrew |title=Wild hummingbirds can use the geometry of a flower array |journal=Behavioural Processes |volume=139 |year=2017|pmid=28161360|issn=0376-6357 |doi=10.1016/j.beproc.2017.01.019 |pages=33–37|hdl=10023/12652 |s2cid=10692583 |hdl-access=free }}</ref>

In at least one hummingbird species &ndash; the [[green-backed firecrown]] (''Sephanoides sephaniodes'') &ndash; flower colors preferred are in the red-green wavelength for the bird's visual system, providing a higher [[contrast (vision)|contrast]] than for other flower colors.<ref name="herrera">{{Cite journal |last1=Herrera |first1=G |last2=Zagal |first2=J. C. |last3=Diaz |first3=M |last4=Fernández |first4=M. J. |last5=Vielma |first5=A |last6=Cure |first6=M |last7=Martinez |first7=J |last8=Bozinovic |first8=F |last9=Palacios |first9=A. G. |year=2008 |title=Spectral sensitivities of photoreceptors and their role in colour discrimination in the green-backed firecrown hummingbird (''Sephanoides sephaniodes'') |journal=Journal of Comparative Physiology A |volume=194 |issue=9 |pages=785–794 |doi=10.1007/s00359-008-0349-8 |pmid=18584181 |hdl-access=free |hdl=10533/142104 |s2cid=7491787|url=http://americanae.aecid.es/americanae/es/registros/registro.do?tipoRegistro=MTD&idBib=3262327 }}</ref> Further, the crown plumage of firecrown males is highly iridescent in the red wavelength range (peak at 650 nanometers), possibly providing a competitive advantage of [[dominance (ethology)|dominance]] when foraging among other hummingbird species with less colorful plumage.<ref name=herrera/> The ability to discriminate colors of flowers and plumage is enabled by a visual system having four single [[cone cell]]s and a double cone screened by [[photoreceptor cell|photoreceptor]] [[oil droplet]]s which enhance color discrimination.<ref name=audubon/><ref name=herrera/>

===Olfaction===

While hummingbirds rely primarily on vision and hearing to assess competition from bird and insect foragers near food sources, they may also be able to detect by [[olfaction|smell]] the presence in nectar of insect defensive chemicals (such as [[formic acid]]) and aggregation [[pheromone]]s of foraging ants, which discourage feeding.<ref name="kim21">{{Cite journal |last1=Kim |first1=Ashley Y. |last2=Rankin |first2=David T. |last3=Rankin |first3=Erin E. Wilson |year=2021 |title=What is that smell? Hummingbirds avoid foraging on resources with defensive insect compounds |journal=Behavioral Ecology and Sociobiology |volume=75 |issue=9 |page=132 |doi=10.1007/s00265-021-03067-4 |issn=0340-5443 |doi-access=free|bibcode=2021BEcoS..75..132K }}</ref>