Description
"Ceratorhina monocerata. Unicorn Auk. Horn-bill Auk. Young: Bill like that of adults in winter, lacking horn, but every way weaker, hardly more than half as large. Mostly dark-colored. No white feathers on side of head. White under parts overlaid and marbled with dark-gray ends of the feathers; black of upper parts brownish. The first spring the horn grows, the accessory piece develops, and the plumage clears up. Nestlings are covered with smoky-brown down." Elliot Coues, 1884
