the crested auklet (aethia cristatella) is a small seabird of the family alcidae , distributed throughout the northern pacific and the bering sea .
the species feeds by diving in deep waters , eating krill and a variety of small marine animals .
it nests in dense colonies of up to 1 million individuals in the bering sea and the sea of okhotsk .
it often breeds in mixed-species colonies with the least auklet , a smaller congener .
the species is known for its sexual ornaments , found in both males and females .
these include colorful plumage with a forehead crest , a striking scent recalling citrus fruit , and a loud trumpet call , all of which appear to have evolved through sexual selection .
the total population is around 6 million , almost half in north america .
it is in general considered to be of least concern , though the alaskan population faces additional threats from predation and oil spills .
the crested auklet was first identified in 1769 by the german zoologist peter simon pallas , who named it aethia cristatella .
the genus aethia includes four auklet species .
there are no subspecies of crested auklet .
the family alcidae consists of many species of shorebirds including other auklets (not in the genus aethia), puffins , razorbills , guillemots , and murres .
the crested auklet can measure 1827 cm (7.110.6 in) in length , 3450 cm (1320 in) in wingspan and weigh 195330 g (6.911.6 oz) .
they have a reddish-orange and yellow tipped bill , yellowish white irises , and white auricular plumes from their eyes to their ears .
their bodies , wings , and tails are primarily dark sooty grey , while their legs and feet are grey and claws black .
the males and females are very similar , although the females have slightly smaller and less curved bills , additionally slightly smaller crests .
crested auklets are known for their forehead crests , which is made of black forward-curving feathers .
these forehead crests are highly variable , and can have between two and twenty three narrow forward curving feathers .
the average auklet has 12 crest feathers , which are of variable length , between 8.1 and 58.5 millimetres .
auklets have auricular plumes and a bright orange bill with curved accessory plates .
like forehead crests , these features vary widely within auklet populations .
the crested auklet is recognized primarily by two characteristics during the breeding season .
the first is its crest , a group of bristle feathers located on top of its head above its eyes .
the second is a social odor that the auklets produce during the breeding season , described as smelling like tangerines .
this odor originates from tiny wick feathers , located in a small patch of skin between the shoulder blades .
in winter plumage , their bills are smaller and dull yellow .
they lack accessory plates and their crest and auricular plumes are reduced .
juveniles are similar to winter adults , but without auricular and crest plumes .
their bills are smaller , and colored a dull brownish yellow .
juveniles take 33 days to reach adult size .
