The Laysan albatross (Phoebastria immutabilis) is a large seabird that ranges across the North Pacific. The Northwestern Hawaiian Islands are home to 99.7% of the population. This small (for its family) gull-like albatross is the second-most common seabird in the Hawaiian Islands, with an estimated population of 1.18 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, on the basis of a specimen from Laysan Island.
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's plumage has been compared to that of a gull, two-toned with a dark gray mantle and wings and a white underside and head.