Hawaiian Duck and Black American Duck . How can I tell them apart ? (1 Viewer)

[Xelioszzapporro!!]

@Bewick @aeshna5 @Earnest lad @THE_FERN @Jeff Hopkins @Welsh Peregrine @Stephen Dunstan @jurek @Southern Viking @TheBlackGrouse @nartreb @Joern Lehmhus @foresttwitcher

So another thread to find out how to differentiate duck species.
This time we have the Hawaiian Duck and I really want to learn what's the difference between it and the Black American Duck. When I look at them , how can I tell the apart ? I would highly appreciate an answer fellas!

This is the Hawaiian Duck



and that's the Black American Duck

 

[qwerty5]

American Black Ducks don't occur on the Hawaiian Islands, so there's really no need to differentiate, but American Black Duck has a high contrast between head and body color, and no white edge to the speculum.

 

[Joern Lehmhus]

Apart from different regions of occurrance and contrasty head , as querty5 said , look at the body feathers of American black duck compared to Koloa (Hawaiian duck). American black duck has these feathers dark brown with a thin pale brown edge and in some feathers some pale markings in the midle of the featehr. But generally that gives a dark body impression. In Hawaiian duck body feathers are patterned much more mallard like with pale brown markings in the feather, not only the pale brown edge.
Also the head is darker and not contrasting with body in Hawaiian duck. And while in American black ducks males have a distinct yellow bill, this is not the case in Hawaiian duck. Also Hawaiian duck is smaller than mallard , while American black duck is mallard-sized.

 

[Joern Lehmhus]

There are also hybrids Hawaiian duck x mallard in some areas on the Hawaiian islands , as these are fully fertile, there can be all kinds of backcrosses and later generation crosses that may be eitehr closer to mallard or to hawaiian duck in such populations.

As theses are also fully fertile, the same applies to Black duck x Mallard hybrids in the range of Black duck