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Rhinoceros Auklet Cerorhinca monocerata


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Rhinoceros Auklet, summer
credit: Tokumi

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Family: Alcidae, Auks, Murres, Puffins view all from this family

Description ADULT SUMMER Has gray-brown upperparts, darkest on crown, nape, back, and wings; neck and chest are also gray-brown, but underparts are otherwise whitish. Has shaggy white plumes running back from eye and from base of bill. Bill is orange-yellow, relatively large (like a scaled-down puffin bill) and with a forward-projecting, pale hornlike plate after which species is named. Iris is white. ADULT WINTER Similar, but white plumes are much-reduced and bill is smaller, duller, and lacks the projecting "horn." JUVENILE Similar to winter adult, but bill is smaller and duller still, and iris is darker.

Dimensions Length: 14 1/2-15 1/2" (37-39 cm)

Habitat Widespread and locally common, breeding colonially on islands and nesting in burrows; activity at colonies is mainly nocturnal. Suffers badly on islands where ground predators have been introduced. Otherwise seen at sea, range extending south in winter to Baja California.

Observation Tips As auklets go, one of the easier species to see, partly because of wide-ranging distribution, but also because it often feeds in inshore seas, even outside breeding season, making it easier to observe from land. You are most unlikely to see the species on land, however, unless you visit a colony after dark.

Range California, Northwest, Alaska, Western Canada

Voice Utters groaning calls, after dark, at colonies. Otherwise silent.

Discussion Relatively large and bulky alcid. Breeding season bill ornamentation is distinctive and diagnostic, even in silhouette. Swims buoyantly and often seen in flocks. Sexes are similar.