https://en.wikipedia.org/wiki/Duck says:

"Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family."

"Ducks are sometimes confused with several types of unrelated water birds with similar forms, such as loons or divers, grebes, gallinules and coots."

#ducksOrNotDucks /1

So far, so good. That sounds simple - swans, geese, grebes and coots are NOT ducks. Got it.

[Grebes are apparently flamingos. But that's a different story].

But then we get onto taxonomy...

#ducksOrNotDucks /2

From Wikipeda/Duck:

".. the so-called 'true ducks' belong to the subfamily Anatinae, which is further split into a varying number of tribes.

The largest of these, the Anatini, contains the 'dabbling' or 'river' ducks ...

The 'diving ducks', also named for their primary feeding method, make up the tribe Aythyini.

The 'sea ducks' of the tribe Mergini are diving ducks which specialise on fish and shellfish and spend a majority of their lives in saltwater."

#ducksOrNotDucks /3

OK, let's see what it says about Anatinae: https://en.wikipedia.org/wiki/Anatinae

"The Anatinae are a subfamily of the family Anatidae (swans, geese, and ducks). Its surviving members are the dabbling ducks"

Dabbling ducks. Right.

But what about diving ducks and sea ducks which you just mentioned before...

#ducksOrNotDucks /4

"Much debate exists about the systematical status and which ducks belong to the Anatinae. Some taxonomic authorities only include the dabbling ducks and their close relatives...

Alternatively, the Anatinae are considered to include most "ducks", and the dabbling ducks to form a tribe Anatini within these."

Well that's clear then. Most "ducks". 😅

#ducksOrNotDucks /5

What about looking higher up, at the family Anatidae: https://en.wikipedia.org/wiki/Anatidae

[skipping section about duck penises.. no-one needs that]

"The systematics of the Anatidae are in a state of flux. Previously divided into six subfamilies, a study of anatomical characters by Livezey suggests the Anatidae are better treated in nine subfamilies.[clarification needed]"

So which is it, 6 sub families? 9 sub families? "Clarification needed", indeed.

#ducksOrNotDucks /6

Ah, it has a "Genera" section. All will become clear.. https://en.wikipedia.org/wiki/Anatidae#Genera

• Subfamily
• Subfamily
• Subfamily
• Subfamily
• Subfamily
• Subfamily
• Subfamily
• Tribe (?!!)
• Tribe
• Unresolved

.. so that's actually 7 subfamilies, 2 tribes and a whole mass of 'unresolved' species.

Just one of those subfamilies includes all swans *and* geese, contradicting what it said above.

#ducksOrNotDucks /7