Bilder av hybrider av vitkindad gås Branta leucopsis – en fotodokumentation av några korsningar med olika Anser-arter

Abstract

This article presents full-body and close-up photographs of hybrids between Barnacle Goose and some Anser goose species. The second parent was in one case a Snow Goose, in five cases a Greylag Goose, in one case a domestic Swan Goose and in one case a Bar-headed Goose. Parentage is considered proven in the Snow Goose and the Greylag Goose hybrids. These hybrids are all rare. The number of individuals is in the magnitude of the estimated total Swedish populations and this is apparently the first report of a Barnacle Goose x domestic Swan Goose hybrid in Sweden. The bill colour pattern varied markedly between the five Greylag Goose hybrid siblings but little from one year to another. In the autumn, Greylag Goose hybrids and to some degree also the Swan Goose hybrid developed a transient white area of the front head next to the bill but a darker and browner colour of the pale cheek area. The various expressions of features inherited from the two parent species are exemplified in the Greylag Goose hybrids.