Admiral Duck was an anthropomorphic duck.
The large-beaked Admiral Duck was apparently one of Donald Duck's ancestor. Donald owns at least two portraits of Admiral Duck in his home: one depicts him wearng a bicorn, while the other one has him wearing a cap and shows the sinking of his boat in the background.
Behind the scenesEditAdmiral Duck was first seen as a portrait in a story by Carl Barks, as of now unidentified. In reference to Barks, Don Rosa drew his own version of Admiral Duck in his 1998 story The Sign of the Triple Distlefink.
In 1999, Admiral Duck is seen in Johannes A. Grote's Duck Family Tree, where he is depicted as a very old member of the (fused on three) McDuck/Duck family. In this version, he is Seafoam McDuck's son and the father of the original owner of the Heirloom Watch. This is, however, obviously impossible. The tree, basing itself on faulty translations, moved Seafoam McDuck two generations farther from Scrooge than he should, leaving Admiral Duck to take the spot; however, once the proper order is restored, the hole disappears, leaving no room for another sailing McDuck in that timeframe. It is much more likely that Admiral Duck was a member of the Duck family.