Editing Hummingbird (section)

==Description==
[[File:Mellisuga helenae Size Comparison.svg|thumb|Size of ''Mellisuga helenae'' (bee hummingbird) {{ndash}} the world's smallest bird {{ndash}} compared to a human hand]]
[[File:Bee hummingbird (Mellisuga helenae) adult male non-breeding.jpg|thumb|Adult male bee hummingbird, [[Cuba]]]]

Hummingbirds are the smallest known and smallest living [[origin of birds|avian theropod dinosaurs]].<ref name="brus">{{cite journal |last1=Brusatte |first1=SL|last2=O'Connor|first2=JK|last3=Jarvis |first3=ED |title=The origin and diversification of birds |journal=Current Biology |volume=25 |issue=19 |pages=R888–98 |date=October 2015 |pmid=26439352 |doi=10.1016/j.cub.2015.08.003 |s2cid=3099017 |doi-access=free |bibcode=2015CBio...25.R888B |hdl=10161/11144 |hdl-access=free }}</ref><ref name="Chiappe">{{cite journal | last=Chiappe | first=Luis M. | title=Downsized dinosaurs: The evolutionary transition to modern birds | journal=Evolution: Education and Outreach| volume=2 | issue=2 | date=16 April 2009 | issn=1936-6426 | doi=10.1007/s12052-009-0133-4 | pages=248–256| s2cid=26966516 | doi-access=free }}</ref><ref name="nhm">{{cite web |last1=Hendry|first1=Lisa |title=Are birds the only surviving dinosaurs? |url=https://www.nhm.ac.uk/discover/why-are-birds-the-only-surviving-dinosaurs.html |publisher=The Trustees of The Natural History Museum, London |access-date=14 April 2023 |date=2023}}</ref> The [[Iridescence|iridescent]] colors and highly specialized feathers of many species (mainly in males) give some hummingbirds exotic common names, such as sun gem, fairy, woodstar, sapphire or [[sylph]].<ref name=eb-h/>

===Morphology===
Across the estimated 366 species, hummingbird weights range from as small as {{convert|2.0|g}} to as large as {{convert|20|g}}.<ref name="eb-h">{{cite web |title=Hummingbird |url=https://www.britannica.com/animal/hummingbird |publisher=Encyclopaedia Britannica |access-date=7 March 2023 |date=2023}}</ref><ref name="smithsonian">{{cite web |title=What is a hummingbird? |url=https://nationalzoo.si.edu/migratory-birds/hummingbirds |publisher=Smithsonian’s National Zoo and Conservation Biology Institute |access-date=7 March 2023 |date=2023}}</ref> They have characteristic long, narrow beaks (bills) which may be straight (of varying lengths) or highly curved.<ref name=eb-h/><ref name=smithsonian/> The bee hummingbird {{ndash}} only {{convert|6|cm}} long and weighing about {{convert|2|g|oz}} {{ndash}} is the world's smallest bird and smallest [[warm-blooded]] [[vertebrate]].<ref name=eb-h/><ref name=ADW>{{cite web|publisher=Animal Diversity Web|title= ''Mellisuga helenae''|last1= Glick|first1=Adrienne|url= http://animaldiversity.org/accounts/Mellisuga_helenae/|date=2002 |access-date=14 April 2023}}</ref>

Hummingbirds have compact bodies with relatively long, bladelike wings having anatomical structure enabling [[helicopter]]-like flight in any direction, including the ability to hover.<ref name=eb-h/><ref name=smithsonian/> Particularly while hovering, the wing beats produce the humming sounds, which function to alert other birds.<ref name=eb-h/> In some species, the tail feathers produce sounds used by males during courtship flying.<ref name=eb-h/><ref name=smithsonian/> One species of hummingbird &ndash; the [[little woodstar]] (''Chaetocercus bombus'') &ndash; has a wing-beat frequency of 99 per second during hovering.<ref name="wilcox2022">{{Cite journal |last1=Wilcox |first1=Sean |last2=Clark |first2=Christopher |year=2022 |title=Sexual selection for flight performance in hummingbirds |url=https://academic.oup.com/beheco/article/33/6/1093/6686581 |journal=Behavioral Ecology |volume=33 |issue=6 |pages=1093–1106|doi=10.1093/beheco/arac075 |url-access=subscription }}</ref> Such extreme flight demands are supported by a high metabolic rate dependent on foraging for sugars from flower nectar.<ref name=Hargrove/><ref name=smithsonian/>

[[File:Ruby Throated Hummingbird, F, leg, 430 ESt. NW, 8.22.12 2013-04-12-14.49.36 ZS PMax (8644622066).jpg|thumb|Close-up of toe arrangement in a [[ruby-throated hummingbird]] foot, showing three claw-like toes forward and one backward.]]
Hummingbird legs are short with [[Dactyly#Anisodactyly|feet]] having [[Bird feet and legs#Tarsometatarsus|three toes pointing forward and one backward]] {{ndash}} the [[hallux]].<ref name="b&b">{{cite web |first1=Emily |last1=Hannemann |title=Hummingbird feet: Can hummingbirds walk? |url=https://www.birdsandblooms.com/birding/attracting-hummingbirds/hummingbird-feet/ |publisher=Birds&Blooms |access-date=4 April 2023 |date=12 May 2022}}</ref><ref name="scoop">{{cite web |title=Do hummingbirds have feet? |url=https://www.wildbirdscoop.com/do-hummingbirds-have-feet.html |publisher=Wild Bird Scoop |access-date=4 April 2023 |date=2023}}</ref> The toes of hummingbirds are formed as [[claw]]s with ridged inner surfaces to aid gripping onto flower stems or petals.<ref name=scoop/> Hummingbirds do not walk on the ground or hop like most birds, but rather shuffle laterally and use their feet to grip while perching, [[preening]] feathers, or nest-building (by females), and during fights to grab feathers of opponents.<ref name=b&b/><ref name=scoop/>

Hummingbirds apply their legs as [[piston]]s for generating [[thrust]] upon taking flight, although the shortness of their legs provides about 20% less propulsion than assessed in other birds.<ref name="reiser">{{cite journal |last1=Tobalske|first1=Bret W. |last2=Altshuler|first2=Douglas L.|last3=Powers|first3=Donald R.|title=Take-off mechanics in hummingbirds (Trochilidae) |journal=The Journal of Experimental Biology |volume=207 |issue=Pt 8 |pages=1345–52 |date=March 2004 |pmid=15010485 |doi=10.1242/jeb.00889 |s2cid=12323960 |doi-access=free |bibcode=2004JExpB.207.1345T }}</ref> During flight, hummingbird feet are tucked up under the body, enabling optimal [[aerodynamics]] and maneuverability.<ref name=scoop/>

Of those species that have been measured during flight, the top flight speeds of hummingbirds exceed {{Convert|15|m/s|km/h mph|abbr=on}}.<ref name=ADW/> During [[Courtship display|courtship]], some male species dive from {{Convert|30|m|ft|sigfig=1}} of height above a female at speeds around {{Convert|23|m/s|km/h mph|abbr=on}}.<ref>{{Cite journal |last1=Clark |first1=C.J. |last2=Dudley |first2=R. |year=2009 |title=Flight costs of long, sexually selected tails in hummingbirds |journal=Proceedings of the Royal Society B: Biological Sciences |volume=276 |issue=1664 |pages=2109–115 |doi=10.1098/rspb.2009.0090 |pmc=2677254 |pmid=19324747}}</ref><ref>{{Cite book |title=The Birds of Ecuador, Field Guide |last1=Ridgely |first1=R.S.|last2=Greenfield|first2= P.G.|publisher=Cornell University Press |year=2001 |isbn=978-0-8014-8721-7 |edition=1}}</ref>

The sexes differ in feather coloration, with males having distinct brilliance and ornamentation of head, neck, wing, and breast feathers.<ref name=eb-h/><ref name=smithsonian/> The most typical feather ornament in males is the [[gorget (bird)|gorget]] {{ndash}} a bib-like iridescent neck-feather patch that changes brilliance with the viewing angle to attract females and warn male competitors away from territory.<ref name=eb-h/>

===Life cycle===
[[File:Allens hummingbird on nest (26198483795).jpg|left|thumb|A nesting female Allen's hummingbird]]
[[File:Allen's Hummingbird Nest (8563916462).jpg|thumb|Each approximately the size of a pea, two eggs in the nest of an Allen's hummingbird]]

Hummingbirds begin mating when they are a year old.<ref name=scien/> Sex occurs over 3–5 seconds when the male [[Bird anatomy#Reproduction|joins its cloaca]] with the female's, passing sperm to fertilize the female's eggs.<ref name="scien">{{cite web |last1=Mohrman |first1=Eric |title=How do hummingbirds mate? |url=https://sciencing.com/hummingbirds-mate-4566850.html |publisher=Sciencing, Leaf Media Group Ltd. |access-date=17 April 2023 |date=22 November 2019}}</ref>

Hummingbird females build a nest resembling a small cup about {{convert|1.5|in|cm}} in diameter, commonly attached to a tree branch using spider webs, [[lichen]]s, moss, and loose strings of plant fibers (image).<ref name=eb-h/><ref name=smithsonian/> Typically, two [[pea]]-shaped white eggs (image) {{ndash}} the smallest of any bird {{ndash}} are incubated over 2–3 weeks in breeding season.<ref name=eb-h/><ref name=smithsonian/> Fed by [[Regurgitation (digestion)|regurgitation]] only from the mother, the chicks [[fledge]] about 3 weeks after hatching.<ref name=smithsonian/><ref name="central">{{cite web |title=Hummingbird facts and family introduction |url=https://www.hummingbirdcentral.com/hummingbird-facts.htm |publisher=Hummingbird Central |access-date=4 April 2023 |date=2023}}</ref>
[[File:Friday's Hummingbird Nest (8819601954).jpg|thumb|Hummingbird nestlings ready to fledge]]

The average lifespan of a [[ruby-throated hummingbird]] is estimated to be 3–5 years, with most deaths occurring in yearlings,<ref name=central/> although one [[Bird ringing|banded]] ruby-throated hummingbird lived for 9 years and 2 months.<ref name="ruby">{{cite web |title=Ruby-throated hummingbird |url=https://www.allaboutbirds.org/guide/Ruby-throated_Hummingbird/ |publisher=All About Birds, Cornell University Laboratory of Ornithology |access-date=23 April 2023 |date=2023}}</ref> Bee hummingbirds live 7–10 years.<ref name=ADW/>

===Population estimates and threatened species===
Although most hummingbird species live in remote habitats where their population numbers are difficult to assess, population studies in the United States and Canada indicate that the ruby-throated hummingbird numbers are around 34 million, rufous hummingbirds are around 19 million, [[black-chinned hummingbird|black-chinned]], [[Anna's hummingbird|Anna's]], and [[broad-tailed hummingbird]]s are about 8 million each, [[calliope hummingbird|calliopes]] at 4 million, and [[Costa's hummingbird|Costa's]] and [[Allen's hummingbird]]s are around 2 million each.<ref name=abc/> Several species exist only in the thousands or hundreds.<ref name=abc/>

According to the [[IUCN Red List|International Union for Conservation of Nature Red List of Threatened Species]] in 2024, 8 hummingbird species are classified as [[critically endangered]], 13 are [[Endangered species|endangered]], 13 are [[vulnerable species|vulnerable]], and 20 species are [[Near-threatened species|near-threatened]].<ref name=iucn/> Two species {{ndash}} the [[Brace's emerald]] (''Riccordia bracei'') and Caribbean emerald (''Riccordia elegans'') {{ndash}} have been declared [[extinction|extinct]].<ref name=iucn/>
[[File:Archilochus colubris (Male).jpg|thumb|left|Male ruby-throated hummingbird (''Archilochus colubris'')]]
Of the 15 species of North American hummingbirds that inhabit the United States and Canada,<ref name=abc/> several have changed their range of distribution, while others showed declines in numbers since the 1970s,<ref name=abc/><ref name=English/> including in 2023 with dozens of hummingbird species in decline. As of the 21st century, rufous, Costa's, calliope, broad-tailed, and Allen's hummingbirds are in significant decline, some losing as much as 67% of their numbers since 1970 at  nearly double the rate of population loss over the previous 50 years.<ref name=abc/><ref name=English/><ref name="cnn">{{cite news |last1=Chillag|first1= Amy |title=These tiny creatures are losing their battle to survive. Here's what we can do to save them |url=https://www.cnn.com/2023/04/21/world/iyw-rufous-hummingbird-tipping-point-extinction-earth-da |access-date=22 April 2023 |work=CNN |date=21 April 2023}}</ref> The ruby-throated hummingbird population {{ndash}} the most populous North American hummingbird {{ndash}} decreased by 17% over the early 21st century.<ref name=English/> Habitat loss, glass collisions, cat predation, [[pesticide]]s, and possibly [[climate change]] affecting food availability, migration signals, and breeding are factors that may contribute to declining hummingbird numbers.<ref name=abc/><ref name=cnn/> By contrast, Anna's hummingbirds had large population growth at an accelerating rate since 2010,<ref name=English/> and expanded their range northward to reside year-round in cold winter climates.<ref name=greig/>

=== Superficially similar species ===
Some species of [[sunbird]]s {{mdash}} an [[Old World]] group restricted in distribution to [[Eurasia]], Africa, and Australia {{mdash}} resemble hummingbirds in appearance and behavior,<ref name=white/> but are not related to hummingbirds, as their resemblance is due to [[convergent evolution]].<ref>{{Cite journal |last1=Prinzinger |first1=R. |last2=Schafer|first2=T.|last3= Schuchmann|first3= K.L. |year=1992 |title=Energy metabolism, respiratory quotient and breathing parameters in two convergent small bird species : the fork-tailed sunbird ''Aethopyga christinae'' (Nectariniidae) and the chilean hummingbird ''Sephanoides sephanoides'' (Trochilidae) |journal=Journal of Thermal Biology |volume=17 |issue=2 |pages=71–79 |doi=10.1016/0306-4565(92)90001-V|bibcode=1992JTBio..17...71P }}</ref>

The [[Hemaris|hummingbird moth]] has flying and feeding characteristics similar to those of a hummingbird.<ref>{{Cite web |first=Beatriz|last=Moisset |date=2022 |title=Hummingbird moth (Hemaris spp.) |url=https://www.fs.fed.us/wildflowers/pollinators/pollinator-of-the-month/hummingbird_moth.shtml |access-date=2 August 2022 |publisher=Forest Service, US Department of Agriculture}}</ref> Hummingbirds may be mistaken for [[hummingbird hawk-moth]]s, which are large, flying insects with hovering capabilities, and exist only in Eurasia.<ref name="white">{{cite web|last=White|first=Richard |title=Hummingbird hawk moth, hummingbird and sunbird |url=https://besgroup.org/2015/09/19/hummingbird-hawk-moth-hummingbird-and-sunbird/ |publisher=Bird Ecology Study Group |access-date=8 March 2023 |date=19 September 2015}}</ref>