the laysan albatross , phoebastria immutabilis , is a large seabird that ranges across the north pacific .
this small (for its family) two-tone gull-like albatross is the second most common seabird in the hawaiian islands , with an estimated population of 2.5 million birds , and is currently expanding (or possibly re-expanding) its range to new islands .
the laysan albatross was first described as diomedea immutabilis by lionel walter rothschild , in 1893, based on a specimen from laysan island .
it is named for laysan , one of its breeding colonies in the northwestern hawaiian islands .
the laysan albatross averages {convert|81|cm|in|abbr=on} in length , and has a wingspan of {convert|195|to(-)|203|cm|in|abbr=on}, .
males , which weigh {convert|2.4|to(-)|4.1|kg|lb|abbr=on}, being larger than females , which weigh {convert|1.9|to(-)|3.6|kg|lb|abbr=on} .
this albatross has blackish-grey upperwing , mantle , back , upper rump , and tail , and their head , lower rump , and underparts are white .
it has a black smudge around the eye , and its underwing pattern varies between individuals , with some having narrower black margins and variable amounts of black in the underwing coverts .
finally , their bill is pink with a dark tip .
juveniles have a grey bill and a dark upper rump .
they do not have a breeding plumage .
the laysan albatross is usually easy to identify , in the north pacific it is simple to separate from the other relatively common albatross , the all black black-footed albatross .
it can be distinguished from the very rare short-tailed albatross by its all dark back and smaller size .
the laysan albatross' plumage has been compared to that of a gull , two tone with a dark grey mantle and wings , and white underside and head .
