Squeezed. The Laysan duck has the most limited range of any duck species in the world- just 11.2 square kilometers- making it especially vulnerable to calamities like disease, competition from introduced animals and extreme weather. Pairs form long-term bonds that can last nearly their entire lives. They spend most of their daylight hours under dense forest cover; at night, they emerge to make meals of brine flies, brine shrimp, moth and beetles. but with little room to roam, danger is never far away.