the pacific loon or pacific diver (gavia pacifica), is a medium-sized member of the loon , or diver , family .
it may be conspecific with black-throated diver/arctic loon , which it closely resembles .
the genus name gavia comes from the latin for "sea mew", as used by ancient roman naturalist pliny the elder .
the specific epithet pacifica is latin for the pacific ocean , the term meaning "peaceful" .
it breeds on deep lakes in the tundra region of alaska and northern canada as far east as baffin island , and in russia east of the lena river .
unlike other loons/divers , this bird may migrate in flocks .
it winters at sea , mainly on the pacific coast , or on large lakes over a much wider range , including china , japan , north korea , south korea , united states and mexico .
it has occurred as a vagrant to greenland , hong kong , great britain , spain , finland and switzerland (dec 2015) .
breeding adults are like a smaller sleeker version of great northern diver/common loon .
they measure 5874 cm (2329 in) in length , 110128 cm (4350 in) in wingspan and weigh 12.5 kg (2.25.5 lb) .
they have a grey head , black throat , white underparts and chequered black-and-white mantle .
non-breeding plumage is drabber with the chin and foreneck white .
its bill is grey or whitish and dagger-shaped .
in all plumages , lack of a white flank patch distinguishes this species from the otherwise very similar black-throated diver/arctic loon .
this species , like all divers/loons , is a specialist fish-eater , catching its prey underwater .
it flies with neck outstretched .
the call is a yodelling high-pitched wailing , as well as harsh growls and barks .
the pacific loon breeds on tundra lakes , and winters in the open ocean or other large bodies of water .
it breeds primarily in northern canada and eastern siberia , and winters along the pacific coast of north america .
