Smew and Sheldrake

Smew noun - Smallest merganser and most expert diver; found in northern Eurasia.

Sheldrake and smew are semantically related. In some cases you can use "Sheldrake" instead a noun "Smew".

Sheldrake noun - Old World gooselike duck slightly larger than a mallard with variegated mostly black-and-white plumage and a red bill.

Smew and sheldrake are semantically related. Sometimes you can replace term "Smew" with "Sheldrake", this nouns are similar.