When referring to a male duck I was told that I should always use the appropriate term "Erpel" when talking about the bird as depicted here:
Wikimedia
Usage of the alternative term "Enterich" should be restricted to a more poetical usage or in a context as shown below:
Wikimedia
Admittedly "Enterich" sounds awkward to me but Duden lists both words as synonyms with approximately same usage frequency. In the German Wikipedia the term "Erpel" seems not to exist in the context of ducks.
Is it true that there is a different usage of both terms? When would we prefer one over the other?
die Bezeichnung für eine männliche Ente, siehe Entenvögel
. On that page, that's right there is no further mentioning of the term. My personal opinion is, that Erpel is the correct biological term, and Enterich is used in the context of stories.