Unsure of what to call these, I sent photos to some waterfowl ID pros who concurred none were clean Ross's Goose, instead probably hybrids (with Ross's x Cackling Goose high on the suspicion list for the adult bird.) Waterfowl expert Steve Mlodinow of the Puget Sound Bird Observatory offered these comments, comparing similar goofy birds he's observed in Washington:
These birds remind me of a series of birds that appeared in se. WA (and one in sw. WA). Ours were all adults, and all had this very dark body, darker than any white-cheeked goose, much like your adult. Head patterns varied, were all something between a Snow or Blue and a Canada. Size was similar to a parvipes. Bill kind of in-between Snow and Lesser Canada. In other words, they looked like your adult, but yours looks more like it has Ross's and Cackling as parents.If he was a bit stymied, then I don't feel so bad for being confused by these birds, too. Steve surmised:
And the imms are even more confusing, because the bills seem to look like they have Snow Goose in 'em, not Ross's, but the birds seem too small to have Snow Goose as a parent. In any case, none of these are blue morph Ross's, nor are they some dwarf Lesser Snow. The head and bill would argue that they couldn't be an aberrantly plumaged Richardson's. At first blush, it seems almost inconceivable that the adult is not part Richy and part Ross's, but then how does one get the super dark body plumage. Then one would have to postulate a BLUE MORPH Ross's x Richardson's, which starts to seem increasingly improbable. But if it waa a blue morph Ross's x Richardsons, then how does the head and neck get to be so white.
The answer, in the end, to this brand of oddity is likely to be had in an aviary... we need to find someone who has a blue morph Snow x white-cheeked Goose and see what they look like and the variation therein. Particularly a heterozygote Blue morph x white-cheeked might produce some of these odd features. In your case, it would likely have to be a heterozygote Ross's x white cheeked. Or then you wonder, could this be one of those odd birds with more than two species genes involved. It happens in captivity, but I don't know if it happens in the wild.Fellow appreciator of odd birds (master bander, ornithologist and my pal, too) Tony Leukering added these comments (ROGO= Ross's Goose, SNGO= Snow Goose, CACG= Cackling Goose in banding codes):
I agree with Steve that none of these birds are blue ROGO. The last one certainly looks a lot like an imm SNGO, but smaller than CACG??? I think that most of us believe that F1 hybrids have to have some combination of parental traits and intermediate traits, but if one looks at dabbler hybrids, we can see that most F1 male hybrids have some patch of white/pale on the head that is not expressed in either parental species. Perhaps, hybrid geese do similar things. Of course, white head and neck could be a dominant gene expressed in such hybrids, too. The adult is certainly somewhat ROGO-like, but, possibly, SNGO x CACG could account for its parentage. However, the bit of blue at the base of the bill (but not nearly as much as is typical of adult ROGO) does suggest ROGO genes (though I don't see much expression of the usual tubercles on the bill of that taxon).So what's going on here? Any one of these would be a head-scratcher, but three such birds at the same spot? I guess the two juvs could be from the same clutch but what about the adult?
And none of the three were associating with each other within the large flock- you'd think if they got there together they'd stick together. Anyone know a waterfowl breeder who may have combos that look like these?
One more odd bird was at least a lot easier to explain- a leucistic Canada Goose. Interesting that the neck and head pigmentation is normal while the body is "dilute", although I've seen other similarly differentiated geese where the head was normal but body abnormal, or visa-versa.