[cobirds] Western vs Clark's Grebe

Hi COBirds,

I'm looking for some help with separating Western and Clark's Grebes in winter.  Certainly Western is our more expected species at this time of year, but now and then I see an Aechmophorus that seems a bit Clarkish.

I know that the pattern of black and white on the face is not definitive for ID in winter.  Are there other clues that are better to look for, like bill color?

For example, here's one I saw recently that had a yellower bill than the other similar birds nearby.  But is it yellow/orange enough?  https://macaulaylibrary.org/asset/277143231

Also see https://www.inaturalist.org/observations/65853723 for another confusing example.

Is the width of the black stripe on the back of the neck a better feature?  Or the flank color?  Should I swim out and try to get a DNA sample?

Any advice gratefully accepted!

Peter Ruprecht

Superior

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