Laysan Island (25° 46' N - 171° 44' W) is a low lying sand island.  Though its length is only 1.6nm, the island is very important as breeding grounds for Hawaiian monk seals and many different species of sea birds. The island is also home to the Laysan Finch (population around 7000) and Laysan Duck (population around 300), and contains a hypersaline (really salty) lake whose size fluctuates with the yearly rainfall amount.  

External link to information on the Laysan Finch:  Bishop Museum's endangered bird list.