Since at least Old English, the word duck has been used to describe the aquatic bird, derived from the verb to duck: Proto-Germanic *dūkaną. However, in most other Germanic languages, a word with a different etymology is used for the bird.
The Wiktionary page on Proto-Germanic *anudz lists the following descendants:
The page for ennet says it's now chiefly dialectal. Which dialect(s) would still use any of these words today?