Raymie's Guide to Domestic Geese

Through the past year, I have noticed that many observations of domestic geese in iNat are misidentified. I don't pretend to be an expert of goose genetics, but I do have a lot of experience with captive waterfowl and will create a guide here to help others understand this confusing group of birds:

Domestic Greylag Goose (Anser anser domesticus):
The Greylag Goose has a shorter neck in comparison to Swan. (Compare two birds in this photo, with Greylag in the back: https://www.inaturalist.org/observations/26797603). Greylag has a wide variety of plumages and bare skin colors. Bare skin may be pink or orange.

Plumage can be confusing; probably the best way to describe it is if it doesn't fit Swan or hybrid, it must be Graylag! Most common plumages include all-white (https://www.inaturalist.org/observations/20070003 , usually has pink skin), similar to wild-type (https://www.inaturalist.org/observations/31779106), and "Blotched" (https://www.inaturalist.org/observations/32441654). If you want to get familiar with the wide variety of plumages, I recommend looking through Google Images and going to local zoos and farm parks.

Domestic Swan Goose (Anser cygnoides domesticus):
The Swan Goose has a much longer than neck than Greylag, and a large knob is always present at the top of the bill (compare in this photo, with Swan in the front: https://www.inaturalist.org/observations/26797603). Swan Goose come in two main colors, brown and white. The brown plumage (https://www.inaturalist.org/observations/31984832) has orange legs and a black bill, with a white ring at the base of the bill. The back of the head and neck is a dark chestnut. White birds (https://www.inaturalist.org/observations/32310394) are all-white with orange legs and bill. Keep in mind occasional white plumaged birds will have faint gray markings. Swan is never blotched. Many Swan Geese have dewlaps, which is rarely (although occasionally) present on Greylag.

Greylag x Swan Goose (Anser anser x cygnoides):
Although hybrid birds have a wider variation in plumage than pure Greylag, many have plumage like this: https://www.inaturalist.org/observations/31301944. Note the dark shading on back of head and neck. Not as dark chestnut as would be present of a dark-plumaged Swan, but different from anything that would be present on a pure Greylag. Hybrids often have a longer neck similar to Swan, but the bill is usually mostly orange, compared to the mostly darker bill of a brown Swan. Hybrids nearly always have a knob on the bill, noticeably smaller than would be present on Swan but larger and more defined than anything present on pure Greylag. Look here for some examples in the variation of plumage in hybrid birds: https://www.inaturalist.org/observations?place_id=any&subview=grid&taxon_id=472287

Keep in mind that many individuals are best left at genus Anser.

Taxa often confused for domestic geese:

Domestic Duck (Anas platyrhynchos domesticus):
White form Domestic Ducks are often confused for Domestic Geese. Their smaller size and differently-shaped beak sets them apart. Domestic Ducks often (though not always) have a curl in their tail. Domestic Geese also never has yellow bills.

https://www.inaturalist.org/observations/32794445
https://www.inaturalist.org/observations/32339369
https://www.inaturalist.org/observations/32259976

Branta x Anser Hybrids:
Hybrids between genuses Branta and Anser are frequently misidentified as domestic geese. Individuals like the following are good examples of "typical" hybrids between the two genera:

https://www.inaturalist.org/observations/32685174
https://www.inaturalist.org/observations/28906983

Just keep in mind that if it shows traits of Canada, it is most likely a hybrid rather than a domestic goose.

Coscoroba Swan:
Generally lighter build and bright red legs and beak differentiate this species from domestic geese.

https://www.inaturalist.org/observations/32447162

Wild-type Swan Goose:
Wild-type Swan Goose resemble a brown Domestic Swan but have a longer, angled bill and lack a knob.

https://www.inaturalist.org/observations/10238718

Publicado por raymie raymie, 17 de septiembre de 2019

Comentarios

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This is a great guideline, thanks!

Publicado por tkoffel hace más de 1 año (Marca)
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Great article, thanks!

Publicado por sam727 hace más de 1 año (Marca)

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