Nutcracker
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For what it's worth, the Howard and Moore checklist attempted to use British spellings for vernacular names of Old World species and American spellings for New World species. Like what you wrote there.
You might reasonably ask "But what about species which can't be classified as Old World or New World?" It turns out that there aren't many such species which have "gr[a/e]y" or "color" in their names. Two or three, I think.
Very sensible - that way fewer toes get trodden on :t:
The number of species in conflict is steadily declining too as genetics shows that many (most?) of the 'Holarctic' species are genetically more distinct than previously thought and are being split - the old Great Grey / Northern Shrikes and Common / Black Scoter name disputes now resolved that way. I suspect Common / Mew Gulls, Common / Red Crossbills, and White-winged / Two-barred Crossbills will be following soon . . .