Escapes, ferals and hybrids. No group of birds epitomises this stigmatised category more than geese … although ducks come a close second. When encountered, examples from this embattled group customarily receive short shrift from birders, who are all too ready to write them off. Having said that, they can provide an interesting distraction during quieter birding moments, giving rise to debate and speculation on origins and parentage.
I’ve been collecting a few photos of ‘dodgy’ geese which have recently been at large here in Northants. Some are relatively straightforward in terms of identification, while others are not so … Here’s a nice easy one.
This is a Canada x Greylag hybrid showing, as expected, mixed features of both species. Hybrids between these two species are remarkably consistent in appearance, with the dark neck and pale cheek patch derived from Canada Goose and the predominantly pale bill and legs and largely grey-brown body from Greylag Goose. I am intrigued by the pale eye-ring since neither Canada nor Greylag has this feature!
The next one is less easy. Although superficially resembling a blue morph Snow Goose there are obvious anomalies.
The bill shape and colour are clearly wrong for that species, there is a sharply demarcated dark breast and a paler, largely grey, body. The elongated, white-fringed, dark-centred tertials and greater coverts of blue morph Snow Goose are absent on this bird and the combination of visible features make this a Canada x Snow hybrid. Such hybrids appear to be uncommon this side of the Atlantic but have been recorded before.
Another Snow Goose hybrid, photographed at Pitsford Reservoir, is depicted below. This individual resembles an intermediate morph Snow Goose (blue morph x white morph)
but such birds normally show the tertials and coverts of blue goose as described above. They are partly elongated on this bird but they remain white. Although there is ‘a lot’ of Snow Goose here I wouldn’t mind betting that a few Greylag genes have crept in somewhere along the way.
Also photographed at Pitsford, this gigantic specimen heads the cast of the gruesome list.
Straightaway, the long neck with a dark line running the length of its rear and the hint of a knob at the base of the bill point to its ‘Chinese’ Goose parentage. ‘Chinese’ Goose is the domesticated form of Swan Goose, which does not have a basal bill knob. This bird looks like a classic domestic Greylag x ‘Chinese’ Goose hybrid. It also looks horribly menacing!
Although certainly not classified as ‘gruesome’ under the current definition, these three Eurasian White-fronted Geese appeared at Stanwick GP during March. One is unusual, however.
The bird on the right has rather large white blaze extending to the crown. This appears to be within the range of variation for Eurasian White-fronted Goose but it is rare and it is also a feature of Gambel’s White-fronted Goose, which breeds in northern Canada. That race, however, has a slightly longer bill as well as a thin yellowish-ochre eye-ring, neither of which is present on this individual.
Thanks are due to Clive Bowley, Bob Bullock, Doug McFarlane and Danny O’Sullivan for supplying the images.