Rhinoceros auklet Cerorhinca monocerata

Identification Tips:

• Length: 11.5 inches
• Sexes similar
• Immature similar to adult basic but lacks plumes and bill and eyes are darker
• Medium to large alcid that dives for food from water surface
• Thick, pointed, yellow bill
• Gray plumage, darker on back
• Belly and undertail coverts mottled white and gray
• Yellow eye
• Pelagic bird only coming ashore to breed

Adult alternate

• Two white plumes on face: one behind the eye and the other behind the bill
• Hornlike projection at base of upper mandible

Adult basic

• White face plumes less distinctive
• Horn absent

Similar species:

Bill shape should render it easily identifiable in all plumages. In basic plumage, the mostly dark plumage is shared by the smaller Cassin's Auklet, whiter-bellied Parakeet Auklet, and larger-billed Tufted Puffin. In alternate plumage, the head plumes and horn are diagnostic.

Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.