Bird hybrids

Usually attempts to care for individuals of another species, with the formation of mixed pairs, are mainly made by males, but they are usually rejected by "alien" females. The first group of reasons for hybridization is “recognition errors”. The likelihood of making mistakes is compounded by the low abundance of their species, which is directly related to difficulties in finding a mating partner and significant social deprivation, increasing the males' motivation for mating with everything that looks like females, a high number of closely related species, etc. Thus, if species-specific there aren’t enough partner birds, individuals of any gender that are predominantly in low social status, or who later flew to their nesting sites, have significantly reduced selectivity in choosing a partner. That is, the chance of the formation of mixed pairs of birds is significantly higher among individuals who failed to create a normal pair at the time when most individuals of this species in a specific population form pairs. For example, in the hybridization zone of the gray and black ravens, individuals with a low rank status may choose to mate individuals of a different species if partners of their species are inaccessible. A similar situation was observed in the hybridization zone of female oatmeal Passerina cyanea and Passerina amoena ^[3] . Females of these species differ externally, and these characters are essential for the choice of males, and therefore interspecific hybridization in this case is already a consequence of the initiative on the part of the females.

In addition, cases of hybridization occur when females are “mistaken” in choosing a partner. “Errors” in the recognition of a partner in females, leading ultimately to the formation of mixed pairs, have been repeatedly described in natural conditions. An example is the hybridization of closely related songbird species, among which there are often cases where males in the hybrid zone learn songs of all three forms (species A, species B, and their hybrid) and have all three songs in their common repertoire, or sing one mixed . At the same time, they have a similar color (for example, Parus ater and Parus melanolophus ). Another example is two species of bulbul in Taiwan: the endemic Pycnonotus taivanus and a subspecies of the formosa species Pycnonotus sinensis, widely distributed on the mainland. Males of these species are not able to distinguish females of their species from females of another species. However, hybridization occurs only between males Pycnonotus sinensis and females Pycnonotus taivanus , since adult (but not young) males of these species differ in the color of their crown, therefore, females Pycnonotus sinensis perceive an adult male Pycnonotus taivanus as a half-adult males of their own species and therefore reject them.

Another reason for interspecific hybridization is the significant similarity of mating rituals and demonstrations in related species, or their complete coincidence. For example, the worldwide distribution of mallard led to widespread crossbreeding with similar but outwardly dissimilar species - Anas rubripes in Canada and the USA , Anas superciliosa in Australia and New Zealand , the Mexican duck Anas diazi , etc., since courtship rituals on the drake behind the female is almost identical to the water. In addition, females can mate with males of other species if they show any super-incentives in the process of courtship - a more complex song, more complex demonstrations, have a high social status, more pronounced mating “jewelry”, etc.

Mezhnyak

Mezhnyak ( Tetrao medius ) - a hybrid of black grouse and capercaillie . Among hybrids there are more males, moreover they are similar to grouse, and there are similar to black grouse. It is believed that the first type is the result of the cross between a male capercaillie and a female grouse, and a second male black grouse and a female capercaillie. Grouse hybrids are more common ^[4] . Mezhnyaks are quite common and combine traits of both black grouse and capercaillie, and the similarity with any of these two species depends on what species the mother belongs to. They can give offspring.

Blue Tit Splash

Tit Pleske or Blue Tit Pleske ^[5] is a hybrid of closely related species: common blue tit and blue tit in their sympatric regions ^[6] . The name was given in honor of the Russian zoologist-systematist, academician of the St. Petersburg Academy of Sciences (1893) Fedor Eduardovich Pleske (1858-1932), who first drew attention to this bird ^[7] . Earlier in the late XIX - early XX centuries ^{[8], the} taxon was erroneously considered as an independent species ^[5] . It is extremely rare. It has a transitional color of common blue tit and blue tit ^[9] . The bird's hat is pale blue. The back is gray-blue with a white spot on the neck. The lower part of the body is usually white with a longitudinal bluish strip in the middle of the abdomen, as well as with a yellow band 11-16 mm wide on the chest. Extreme helmsmen have a white outer fan and a white top. Minor flyworms and their large horsemans have white peaks 4-7 mm long. Primary fly coverts are distinguished by shorter white peaks 1.5-3 mm long ^[10] .

The hybrid is capable of reproduction. In the eighties of the XIX century, a white blue tit appeared in such areas of western Russia, where previously there was only an ordinary blue tit, but since 1889 the white blue tit disappeared from there again, and at the border of the contact of these two species a hybrid called the tit of Pleske appeared ^[11] . Starting from the middle of the 20th century, meetings were observed with a hybrid in Europe from the Leningrad Region to the Netherlands during the autumn migration or during wintering ^[10] .

Mulard

Mulard is an interspecific hybrid obtained by crossing the drakes of musky ducks with domestic ducks of the species Peking White, Orgpington, Rouen and White Aloe. Mulard, not found in the wild due to the different geographical ranges of common mallard ( Eurasia ) and wild musky duck ( South America ), are bred only on the initiative of a person to correct the deficiencies that exist in these breeds. The most widespread mullards were in France, the USA , England, and also in Southeast Asia ^[12] . As a rule, female muleards are grown for meat, and males for foie gras . Traditionally foie gras were obtained from geese . However, since the 1960s, most farms have switched to these hybrid ducks ^[13] .

Banduk

Banduque ( Carduelis carduelis × Serinus canaria ) is a hybrid of carduelis and canary . The hybrid combines the features of the color of carduelis and the ability to sing canaries. In birds obtained from a green or yellow canary, the back has a greenish color, chest with yellowness, and the mask around the beak is orange. Sometimes there are almost entirely yellow birds with an orange mask. In hybrids from a carduelis with a red canary, the chest is pink, and the mask is almost red in color, as in a carduelis ^[14] .

Parrot Hybrids

Hybrids are traditionally bred to obtain new types of color. Some hybrids of macaw parrots are second or third generations. The result of hybridization for many species is sterile offspring. But the first and second generations are able to give offspring. A higher level of sterility of hybrids is observed in the third generation and beyond.

• Hybrids between members of different families
  • Neophema chrysostoma x Nymphicus hollandicus
• Intergeneric hybrids
  • Anodorhynchus hyacinthinus x ara ararauna - galoshua
  • Ara chloroptera x Ara militaris - calico
  • Ara chloroptera x Ara ararauna - harlequin
  • Ara macao x Ara ambigua - werde
  • Ara macao x Ara chloroptera - ruby ​​macaw
  • Ara macao x Ara militaris - shamrock
  • Ara ararauna x ara macao - catalina
  • Ara ararauna x Ara militaris - milligold
  • Ara chloroptera x Ara ambigua - buffing
  • Ara ararauna x Ara ambigua - buffgold
  • Ara militaris x Anodorhynchus hyacinthinus - millicint
  • Eolophus roseicapillus x Nymphicus hollandicus
  • Eolophus roseicapillus x Cacatua galerita
  • Eolophus roseicapillus x Licmetis spp.
  • Platycercus eximius x Psephotus haematonotus
• Interspecific hybrids
  • Amazona ochrocephala x Amazona auropalliata
  • Ara ararauna x Amazona macao
  • Aratinga jandaya x Aratinga solstitialis

Other Hybrids

• Hybrids of geese : Canada Goose x Gray Goose , Canada Goose x White Goose , Red-breasted Goose x Canadian Goose , Canadian Goose x White-fronted Goose , White- faced Goose x Canadian Goose .
• Intergeneric hybrids of swans and geese ( Cygnus sp. X Branta sp. )
• Swan Hybrids - Black Swan x Mute Swan
• Hybrids between ducks of the genus Aythya
• Poultry hybrids, including chicken x common pheasant , chicken x guinea fowl , guinea fowl x Indian peacock , numerous hybrids of various species of pheasants (for example, Chrysolophus pictus x Chrysolophus amherstiae , blue grouse x common pheasant ) ^{[15] [16] [17] [18]} .
• Cases of hybridization of a Siberian Crane with a gray crane were noted ^[19]
• Seagulls - hybrid forms of the Larus argentatus x cachinnans x fuscus complex are known ^[20] .
• Great spotted eagle x Lesser spotted eagle ^[21]
• Birds of paradise include several examples of both intraspecific and interspecific hybridization.
• Hybrids of the Corvus genus, such as rook x jackdaw , rook x raven , black crow x gray crow (Some systematists consider the gray crow as a race or subspecies of the black crow. In the overlapping zone of their ranges, mixed pairs and hybrids with different variants of intermediate coloring are found )
• With artificial breeding, it is possible to obtain an interspecific hybrid of a vakhir and a gray pigeon .

• A Bird Hybrids Database - A searchable bird hybrid database.
• Interspecific Hybridization Factors in Birds