0 the rhinoceros auklet (cerorhinca monocerata) is a seabird and a close relative of the puffins .
1  it is the only living species of the genus cerorhinca .
2  given its close relationship with the puffins , the common name rhinoceros puffin has been proposed for the species .
3 it ranges widely across the north pacific , feeding on small fish and nesting in seabird colonies .
4  its name is derived from a horn-like extension of the beak .
5  this horn is only present in breeding adults , and like the elaborate sheath on the bill of puffins is shed every year .
6 the rhinoceros auklet (also known as the rhino auklet , horn-billed puffin , or unicorn puffin), is a medium-sized auk with a large , strong , orange/brown bill (with the 'horn' protruding from it) .
7  the plumage is dark on top and paler below; breeding adults (both male and female) possess white plumes above the eyes and behind the bill .
8  males are slightly larger than females (about 10% in mass) .
9 the rhinoceros auklet is a north pacific auk that breeds from california (the channel islands) to the aleutian islands in alaska in north america; and hokkaid and honsh , japan , as well as north korea and sakhalin island in asia .
10  it winters both in offshore and inshore waters , exhibiting some migration .
11 the rhinoceros auklet nests in burrows dug into the soil , or in natural caves and cavities between 1 and 5 m deep .
12  it prefers nesting sites on slight inclines to aid take-off , as it is a poor flier .
13  a single egg is incubated by both parents for 45 days .
14  the semiprecocial chick is then fed each night with a bill full of fish (in the manner of puffins) for 50 days; this nocturnal behaviour is believed to be a response to predation and kleptoparasitism by gulls .
15 at sea , rhinoceros auklets feed on fish , with some krill and squid taken also .
16  they feed inshore during the breeding season in the midwater .
17   to catch their prey , they dive as deeply as 57 meters (187 ft) for as long as 148 seconds .
