Re: [cobirds] Interesting goose at Dodd Reservoir, Boulder County

Hi Randy,

One thing I find useful when identifying dark morph Snow Geese is the tertial feathers that flop over the flanks and rump when the bird is standing or swimming. On a dark morph Snow, these will be black with distinctive white outlines. On hybrids, they're almost always solid brown like on the Canada or Cackling parent. 

Sometimes you can also see the nice blue-gray leading edge of the wing even when a dark morph Snow has its wings folded. Again, the whole wing is usually brown on a hybrid.

See for example https://macaulaylibrary.org/asset/36514851

Based on that, I'd call the bird in your photos a hybrid. I personally have a hard time deciding what Anser/Branta mix is in most hybrids (except for tiny Ross's/Cackling hybrids), so maybe someone else will want to offer advice there.

Peter Ruprecht

Superior

On Wed, Jan 7, 2026 at 4:01 PM Randy Siebert <rlsiebert52@gmail.com> wrote:

I got photos of a goose which is either a blue morph Snow Goose or a hybrid. A nice Greater White-fronted Goose was around for size comparison.

Opinions will be appreciated and may save me dealing with an eBird reviewer.

You can see them at:

eBird Checklist - 7 Jan 2026 - Dodd Reservoir - 12 species

Randy Siebert

Lafayette, Boulder County

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