Editing Hummingbird (section)

== Migration ==

Relatively few hummingbirds migrate as a percentage of the total number of species; of the roughly 366 known hummingbird species, only 12–15 species migrate annually, particularly those in North America.<ref name="lowe">{{cite web |last1=Lowe|first1=Joe |title=Do hummingbirds migrate? |url=https://abcbirds.org/blog/do-hummingbirds-migrate/ |publisher=American Bird Conservancy |access-date=8 March 2023 |date=12 September 2019}}</ref> Most hummingbirds live in the [[Amazonia]]-Central America [[tropical rainforest]] belt, where seasonal temperature changes and food sources are relatively constant, obviating the need to migrate.<ref>{{cite web |last1=Godshalk |first1=Katrina |title=Hummingbird migration |url=https://www.highcountrygardens.com/gardening/best-plants-hummingbird-migration |website=High Country Gardens |access-date=16 January 2023}}</ref> As the smallest living birds, hummingbirds are relatively limited at conserving heat energy, and are generally unable to maintain a presence in higher latitudes during winter months, unless the specific location has a large food supply throughout the year, particularly access to flower nectar.<ref name="lopez">{{cite journal |last1=López-Segoviano |first1=Gabriel |last2=Arenas-Navarro |first2=Maribel |last3=Vega |first3=Ernesto |last4=Arizmendi |first4=Maria del Coro |title=Hummingbird migration and flowering synchrony in the temperate forests of northwestern Mexico |journal=PeerJ |volume=6 |issue= |pages=e5131 |date=2018 |pmid=30002968 |pmc=6037137 |doi=10.7717/peerj.5131 |doi-access=free }}</ref> Other migration factors are seasonal fluctuation of food, climate, competition for resources, predators, and inherent signals.<ref name=lopez/>

Most North American hummingbirds migrate southward in fall to spend winter in Mexico, the Caribbean Islands, or Central America.<ref name="migrate">{{Cite web |date=2023 |title=Hummingbird migration |url=https://www.hummingbirdcentral.com/hummingbird-migration.htm |access-date=28 August 2018 |publisher=Hummingbird Central}}</ref> A few species are year-round residents of [[Florida]], California, and the southwestern desert regions of the US.<ref name=migrate/> Among these are Anna's hummingbird, a common resident from southern Arizona and inland California, and the [[buff-bellied hummingbird]], a winter resident from Florida across the Gulf Coast to [[South Texas]].<ref name=migrate/> Ruby-throated hummingbirds are common along the [[Atlantic flyway]], and migrate in summer from as far north as [[Atlantic Canada]], returning to Mexico, South America, southern Texas, and Florida to winter.<ref name=abc/><ref name=migrate/> During winter in southern [[Louisiana]], black-chinned, buff-bellied, calliope, Allen's, Anna's, ruby-throated, rufous, broad-tailed, and broad-billed hummingbirds are present.<ref name=migrate/>

The rufous hummingbird breeds farther north than any other species of hummingbird, spending summers along coastal British Columbia and Alaska, and wintering in the southwestern United States and Mexico,<ref name=migrate/> with some distributed along the coasts of the subtropical Gulf of Mexico and Florida.<ref name="Cornell"/> By migrating in spring as far north as the [[Yukon]] or southern Alaska,<ref name="Cornell">{{Cite web |date=2023 |title=Rufous hummingbird |url=http://www.allaboutbirds.org/guide/Rufous_Hummingbird/lifehistory |access-date=29 April 2023 |publisher=Cornell University Laboratory of Ornithology}}</ref> the rufous hummingbird migrates more extensively and nests farther north than any other hummingbird species, and must tolerate occasional temperatures below freezing in its breeding territory. This cold hardiness enables it to survive temperatures below freezing, provided that adequate shelter and food are available.<ref name="Cornell"/>

As calculated by [[displacement (vector)|displacement]] of body size, the rufous hummingbird makes perhaps the longest migratory journey of any bird in the world. At just over {{convert|3|in|cm}} long, rufous hummingbirds travel {{convert|3900|mi}} one-way from Alaska to Mexico in late summer, a distance equal to 78,470,000 body lengths, then make the return journey in the following spring.<ref name=lowe/><ref name="Cornell"/> By comparison, the {{convert|13|in|cm}}-long [[Arctic tern]] makes a one-way flight of about {{convert|18,000|km}}, or 51,430,000 body lengths, just 65% of the body displacement during migration by rufous hummingbirds.<ref name="Cornell"/>

The northward migration of rufous hummingbirds occurs along the [[Pacific flyway]],<ref>{{Cite web |title=Map of rufous hummingbird migration, Spring 2023 |url=https://maps.journeynorth.org/map/?map=hummingbird-rufous-first&year=2023|date=29 April 2023 |access-date=29 April 2023 |publisher=Journey North, Annenberg Learner}}</ref> and may be time-coordinated with flower and tree-leaf emergence in early spring, and also with availability of insects as food.<ref name="Cornell"/> Arrival at breeding grounds before nectar availability from mature flowers may jeopardize breeding opportunities.<ref>{{Cite journal |last1=McKinney |first1=A.M. |last2=Caradonna |first2=P.J. |last3=Inouye |first3=D.W. |last4=Barr |first4=B |last5=Bertelsen |first5=C.D. |last6=Waser |first6=N.M. |year=2012 |title=Asynchronous changes in phenology of migrating broad-tailed hummingbirds and their early-season nectar resources |url=https://pure.au.dk/ws/files/83236748/McKinney_et_al._2012_with_cover.pdf |journal=Ecology |volume=93 |issue=9 |pages=1987–993 |doi=10.1890/12-0255.1 |pmid=23094369|bibcode=2012Ecol...93.1987M }}</ref>