Canada Goose x (Greylag Goose x Swan Goose) trigen

Canada Goose Branta canadensis x domestic (Greylag Goose Anser anser x Swan Goose Anser cygnoides) trigen

Many domestic geese contain a mix of Swan Goose and Greylag Goose genes and when such mixed-species domestic geese hybridise with Canada Geese the offspring may resemble either Canada Goose x Swan Goose hybrids or Canada Goose x Greylag Goose hybrids - sometimes both in a single brood. Consequently it is often impossible to tell whether the domestic goose parent of a domestic goose x Canada Goose hybrid was a mixed-species domestic goose or a single species. For all of the birds on this page there is some reason to think that the domestic goose parent may have had both Swan Goose and Greylag Goose ancestry.

This bird looked a lot like a typical Canada Goose x Greylag Goose hybrid, but the predominantly black bill and slight bulge at its base probably indicate domestic Swan Goose genes.

probable Canada Goose x (domestic Swan Goose x Greylag Goose) trigens (with apparent domestic Greylag Goose x Swan Goose hybrid and Canada Goose), Ythan Estuary (Grampian, UK), 18th March 2014

The next set of birds below were a group of eight, accompanied by a domestic goose and a Canada Goose. The domestic goose closely resembled domestic Greylag Goose but showed some features suggesting Swan Goose ancestry, including a dark nail. The hybrids varied in appearance, some looking much like typical Greylag Goose x Canada Goose hybrids. Others were longer-necked, as is often the case with Swan Goose x Canada Goose hybrids. Curiously some of these birds showed darker body plumage (with contrasting paler bellies) than is typical of Greylag Goose x Canada Goose hybrids, or Swan Goose x Canada Goose hybrids - not sure what significance this has, if any, but I don't see any reason to invoke any of the species that might be expected to show this (White-fronted Goose sp. hybrids and Snow Goose hybrids can show such dark plumage, but no evidence of their involvement here).

probable Canada Goose x (domestic Swan Goose x Greylag Goose) trigens (with apparent domestic Greylag Goose x Swan Goose hybrid and Canada Goose), Nun's Bridge, Thetford (Norfolk, UK), 9th February 2013

These four hybrids appeared to be a family party. In most respects they resembled typical Canada Goose x Greylag Goose hybrids but two had mostly black bills which is not normal for such a hybrid and some had (to varying extents) white speckling down the neck. The most likely explanation is that the grey parent had mixed Greylag and domestic Swan Goose ancestry.

probable Canada Goose x (domestic Swan Goose x Greylag Goose) trigens (with Greylag Geese), Drift Reservoir (Cornwall, UK), 1st October 2005

For comparison, here are photos of the parent species.

Canada Goose, Swanton Morley fishing lakes (Norfolk, UK), 16th August 2008 and Greylag Goose x Swan Goose hybrid, Nun's Bridge, Thetford (Norfolk, UK), 9th February 2013

For more photos of these species follow the links below: