Bird hybrid

{{short description|Bird with two different species as parents}}

File:Hybrid tauraco -Bird Kingdom, Niagara Falls, Canada-8a (1).jpg ]]

File:Catalina macaw.jpg - a blue-and-yellow macaw × scarlet macaw hybrid]]

A bird hybrid is a bird that has two different species as parents. The resulting bird can present with any combination of characteristics from the parent species, from totally identical to completely different. Usually, the bird hybrid shows intermediate characteristics between the two species. A "successful" hybrid is one demonstrated to produce fertile offspring. According to the most recent estimates, about 16% of all wild bird species have been known to hybridize with one another; this number increases to 22% when captive hybrids are taken into account. Several bird species hybridize with multiple other species. For example, the mallard (Anas platyrhynchos) is known to interbreed with at least 40 different species. The ecological and evolutionary consequences of multispecies hybridization remain to be determined.

In the wild, some of the most frequently reported hybrids are waterfowl, gulls, hummingbirds, and birds-of-paradise.{{Cite web|url=https://www.beautyofbirds.com/birdsofparadisehybrids.html|title=Hybrid Species of Bird of Paradise or Cendrawasih {{!}} Beauty of Birds|website=www.beautyofbirds.com|access-date=2018-12-04}} Mallards, whether of wild or domestic origin, hybridize with other ducks so often that multiple duck species are at risk of extinction because of it.{{Cite web |url= https://www.allaboutbirds.org/guide/Mottled_Duck/overview|title=Mottled Duck Overview, All About Birds, Cornell Lab of Ornithology |website= www.allaboutbirds.org |access-date=2018-12-04}}{{Cite web |url= https://birdsna.org/Species-Account/bna/species/hawduc/introduction |title= Hawaiian Duck - Introduction |website= Birds of North America Online, birdsna.org |access-date=2018-12-04}} In gulls, Western × Glaucous-winged Gulls (known as "Olympic Gulls") are particularly common; these hybrids are fertile and may be more evolutionarily fit than either parent species.{{Cite web |url= http://birdhybrids.blogspot.com/2014/06/western-gull-x-glaucous-winged-gull.html |title=Bird Hybrids: Western Gull × Glaucous-winged Gull |last=Appleton |first=Dave |date=2014-06-05 |website= Bird Hybrids |access-date=2018-12-04}} At least twenty different hummingbird hybrid combinations have been reported, and intergeneric hybrids are not uncommon within the family.{{Cite web|url=https://avianhybrids.wordpress.com/apodiformes/|title=Apodiformes|last=says|first=It’s complicated: Hybrid hummingbirds in Mexico-Avian Hybrids|date=2014-12-12|website=Avian Hybrids|access-date=2018-12-04}}{{Cite web|url=http://westtexashummingbirds.com/information/species-accounts/hybrids/|title=westtexashummingbirds.com: Hybrids|access-date=2018-12-04}}

Wood-warblers are known to hybridize as well, and an unusual three-species warbler hybrid was discovered in May 2018. Hybridisation in shorebirds is unusual but reliably recorded.{{cite journal|author=Jehl, J. R. Jr.|year=1985|title=Hybridization and evolution of oystercatchers on the Pacific Coast of Baja California|journal=Ornithological Monographs|volume=36|issue=36|pages=484–504|doi=10.2307/40168300|jstor=40168300}}{{cite journal|author=Jonsson, Lars|year=1996|title=Mystery stint at Groote Keeten: First known hybrid between Little and Temminck's Stint?|journal=Dutch Birding|volume=18|pages=24–28}}{{cite book|url=https://books.google.com/books?id=MwInO7z_Y3oC&pg=PA170|title=Handbook of Avian Hybrids of the World|last=McCarthy|first=Eugene M.|publisher=Oxford University Press|year=2006|isbn=978-0-19-518323-8|location=Oxford, UK|page=170}}{{cite journal|author1=McLaughlin K. A.|author2=Wormington, A.|year=2000|title=An apparent Dunlin × White-rumped Sandpiper hybrid|journal=Ontario Birds|volume=18|issue=1|pages=8–12}}{{cite journal|author=Millington, Richard|year=1994|title=A mystery Calidris at Cley|url=http://www.birdingworld.freeserve.co.uk/CleyCalidrisArticle.htm|url-status=dead|journal=Birding World|volume=7|issue=2|pages=61–63|archive-url=https://web.archive.org/web/20040617170807/http://www.birdingworld.freeserve.co.uk/CleyCalidrisArticle.htm|archive-date=2004-06-17}}{{cite journal|author=Parker, Shane A.|year=1982|title=A new sandpiper of the genus Calidris|journal=South Australian Naturalist|volume=56|pages=63}}{{cite book|title=Shorebirds of North America: a photographic guide|author=Paulson, Dennis R.|publisher=Princeton University Press|year=2005|isbn=978-0-691-12107-9|place=Princeton, N.J.}}{{cite journal|author=Pierce, R. J.|year=1984|title=Plumage, morphology and hybridisation of New Zealand Stilts Himantopus spp|url=http://www.notornis.org.nz/free_issues/Notornis_31-1984/Notornis_31_2.pdf|url-status=dead|journal=Notornis|volume=31|pages=106–130|archive-url=https://web.archive.org/web/20071024010943/http://www.notornis.org.nz/free_issues/Notornis_31-1984/Notornis_31_2.pdf|archive-date=2007-10-24}}

Numerous gamebird, domestic fowl and duck hybrids are known. Captive songbird hybrids are sometimes called mules.{{cite web|title=The National British Bird & Mule Club|url=http://www.birdinfo.co.uk/sites/natbritishbirdmuleclub/club_history.htm|access-date=18 January 2018}} Numerous hybrid macaws exist in aviculture and occasionally occur in the wild. Some of these hybrid parrots are fertile with both the parent species and other hybrids.{{Cite web|url=https://www.beautyofbirds.com/hybridmacaws.html|title = Hybrid Macaws & Mutations | Beauty of Birds}}{{Cite web|url=https://www.thesprucepets.com/hybrid-macaws-390828|title = These Are the 21 Types of Hybrid Macaws}}

The scientific literature on hybridization in birds has been collected at the Avian Hybrids Project.{{Cite web|url=https://avianhybrids.wordpress.com/|title=The Avian Hybrids Project|last=Ottenburghs |first=Jente |website=Avian Hybrids |access-date=2018-07-21}}

The reality of bird hybrids also calls into question modern definitions of the word "species". Throughout literature, there tends to be a general vagueness regarding the word "species" and how it should be defined. Birds serve as an excellent example of this fluidity due to the remarkable cross-breeding opportunities.{{Citation needed|date=May 2021|reason=Species fluidity is highly documented}}