The Red-throated Loon is the smallest and most slender of the loons. It has a thin bill that points slightly upward. In breeding plumage, it has a blackish-brown back, a gray head and neck, and a deep red throat. In non-breeding plumage, it has a gray back speckled with white, giving the bird an overall light gray appearance. The throat and face are white, with the white on the face extending above the eyes; the crown of the head is dark. Juveniles are brownish-gray. Under-parts are white in all plumages.