What specific plumage feature helps lock in the identification of a male Common Eider's head pattern?
Answer
A patch of pale green plumage on the nape.
The identification of the male Common Eider is confirmed by its head pattern, which includes a distinct black cap and, crucially, a patch of pale green plumage located on the nape, or the back of the neck.
Related Questions
What is the primary visual clue regarding size when identifying an eider duck in the water?What specific plumage feature helps lock in the identification of a male Common Eider's head pattern?What feature primarily distinguishes a male King Eider from a male Common Eider on the head and bill?What is the general appearance of female eiders?When separating a female Common Eider from an American Black Duck, what structural difference is noted?What is the defining characteristic of the bill structure common to all eiders?What type of vocalization is known for the male Common Eider?How does the nape plumage of the male Common Eider differ from the head coloring of the male King Eider?In which type of environment are eiders strongly associated?What key facial feature is present across several female eider species, including the Common Eider?What is consistent regarding the heavy structure and mass of eiders across both sexes?