Tule White-fronted Goose Anser albifrons elgasi, Gambell's White-fronted Goose Anser albifrons gambelli and Pacific White-fronted Goose Anser albifrons sponsa

These three forms of Greater White-fronted Goose breed in western North America. Birds wintering west of the Rockies are, I understand, a mixture of Tule elgasi and Pacific sponsa, whereas I gather Gambell's gambelli normally winters east of the Rockies. I hasten to add that I have no expertise on separating these three taxa!

The photos below comprise a mixture of captive birds where I was informed of the identity by their owner and wild birds (one west of the Rockies, one in the Rockies) one of which I have attempted to identify to form but (as always, but especially here) I am open to feedback.

I suspect the following individual is a Tule White-fronted Goose elgasi, given the pale whitish base to the bill evident in some photos, the yellow orbital ring. I think the bill shape is probably ok for Tule, but these are taxa I need more experience of to call with any confidence.

Greater White-fronted Goose, perhaps Tule White-fronted Goose elgasi (with a domestic goose with mixed Greylag and Swan Goose ancestry in the background), Neary Lagoon (California, USA), 1st May 2005

These were too distant to get good photos and may not be clear enough to identify to subspecies, at least not with my lack of experience with the North American taxa.

Greater White-fronted Geese (with an American Wigeon in the foreground), Creston Valley (British Columbia, Canada), 18th September 2006

I was told that these two captive birds were Tule. The head isn't as dark as I would have expected, but the pale base to the bill and the yellow orbital ring are good elgasi characters.

captive Tule White-fronted Geese elgasi, private collection at Wereham (Norfolk, UK), 5th May 2017

I was told that these two captive birds were Pacific. At least one of them has an obvious orbital ring but even though that's often cited as a Tule character I don't suppose it's a problem for other taxa (for example I know Russian albifrons sometimes shows this, despite it not really being a classic albifrons feature). I think the bird shown close-up seems to have a slight bump on the culmen so maybe not the best bird to judge bill shape on? I think the peachy bill tones are good for Pacific sponsa.

captive Pacific White-fronted Geese sponsa (with Cackling Geese), private collection at Wereham (Norfolk, UK), 5th May 2017