There is no American loon that is predominately black. Probably it is the double-crested cormorant, Phalacrocorax auritus [AOU, 120], although the common loon, Gavia immer [AOU, 7], is dark gray on its head and back in winter. Less likely this could be the widely distributed American coot, Fulica americana [AOU, 221], although the captains later refer to that species as a "black duck" ([November 30, 1805], and [March 10, 1806]). Burroughs, 224–25.
Ondatra zibethicus. Hall, 2:824–28.