A bird hybrid is a bird that has two different species as parents. The resulting bird can present with any combination of characters 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.
The description of bird hybrids results from observations in nature combined with those obtained in captivity such as in zoos per example.
Examples sorted taxonomically
- Goose hybrids, including Canada goose x greylag goose, emperor goose x Canada goose, red-breasted goose x Canada goose, Canada goose x white-fronted goose and barnacle goose x Canada goose see also Gamebird hybrids.
- "Swoose" (swan x goose) 
- Hybrid swans, such as the Black Swan x Mute Swan (Cygnus atratus x Cygnus olor)
- Hybrid ducks of the genus Aythya, including birds which are a mixture of tufted duck, greater scaup, common pochard, ferruginous duck and ring-necked duck
- Other hybrid ducks, including northern pintail x mallard, ruddy duck x white-headed duck, ruddy shelduck x common shelduck, white-faced whistling duck x plumed whistling duck, Baikal teal x northern pintail, hooded merganser x smew, Eurasian wigeon x American wigeon and mallard x New Zealand black duck. See also Mariana mallard and Gamebird hybrids.
- Gamebird hybrids, including capercaillie x common pheasant, capercaillie x black grouse (rackelhahn) and Lady Amherst's pheasant x golden pheasant see also Gamebird hybrids
- Hybrids of domestic fowl, including chicken x common pheasant, chicken x guinea fowl, and guinea fowl x peafowl see also Gamebird hybrids
- Hybrid gull, including glaucous gull x herring gull and lesser black-backed gull x yellow-legged gull
- see main article hybridisation in gulls
- Several other families of Charadriiformes (shorebirds/waders)
- Red kite x black kite (unintended, in a falconry center)
- Eagle hybrids, including golden eagle, x eastern imperial eagle, lesser spotted eagle x greater spotted eagle,
- Falcon hybrides include the perlin: peregrine falcon x merlin
- Penguins hybrid, including
- interspecific hybrids:
- Eudyptes chrysolophus (macaroni penguin) X Eudyptes .sp (rockhopper penguin) X Eudyptes schlegeli (royal penguin) commonly known as the 'machopper penguin'
- Aptenodytes patagonicus (king penguin) X Aptenodytes forsteri (emperor penguin) commonly named the 'kingemperor' hybrid penguin.
- Eudyptes chrysolophus (macaroni penguin) X Eudyptes .sp (rockhopper penguin) commonly known as the 'machopper penguin'
- Stork hybrid, including
- Parrot hybrids, including
- interfamilial hybrids:
- intergeneric hybrids:
- interspecific hybrids:
- Ara ararauna (blue and gold macaw) X A. macao (scarlet macaw) commonly known as either the 'catalina' (worldwide) or the 'rainbow' (primarily in Australia) hybrid macaw ;
- intraspecific hybrids:
- Eclectus roratus solomonensis (Solomon Island's eclectus) X E. r. vosmaeri (Vosmaeri's eclectus) commonly known as the 'solo-vos' eclectus,
- Captive songbird hybrids, such as mules, (canary x British finch) and crosses of finch species.
- Corvus hybrids such as (rook x jackdaw), rookdaw (rook x raven) rooven and carrion crow x hooded crow
- Birds of paradise include several examples of both intraspecific and interspecific hybridisation.
- Species problem
- Allopatric vs. sympatric speciation
- Sexual selection and speciation
- Islands as "natural laboratories" for exploring speciation
- Species concepts (biological vs. phylogenetic)
- "Instant speciation" via polyploidy etc.
- Ecological vs. genetic speciation
- Punctuated equilibrium evolution and speciation
- Shifting balance theorem
- Haldane's rule
- An introduction to Speciation: Speciation and Hybridization
- A Bird Hybrids Database (Search by name of bird) is available online for free. As of April 3rd 2010, it contains 3,169 unique Bird Hybrids from 2,035 references. The English nomenclature used for the database is Sibley's or Howard's. The references are available by clicking on the bird hybrid name. http://www.bird-hybrids.com/engine.php?LA=en
- Bird Hybrids Mailing List - http://www.bird-hybrids.com/Mailing_list_en.php
- The World's first Nymphicus hollandicus (cockatiel parakeet) X Eolophus roseicapillus (rose-breasted aka galah cockatoo) inter-generic hybrid: http://www.talkingbirds.com.au/galatiel.php
- Scarlet-chest parrot breeds with princess parrot: http://www.talkingbirds.com.au/worldfirst.php
- Images and descriptions of hybrid macaws: http://animal-world.com/encyclo/birds/macaws/information/hybrid.htm