Conservation of oceanic island species presents many ecological and logistical challenges. The Northwestern Hawaiian Islands (NWHI) include 300,000 km2 of ocean waters and 10 groups of sub-tropical islands and atolls of high conservation value. Designated as Papahanaumokuakea Marine National Monument, the islands provide habitat for four endangered species of terrestrial birds. Despite their protected status, many of these species are faced with the ongoing threat of extinction due to stochastic catastrophes such as disease, invasive mammal introductions, tsunamis, and hurricanes. To reduce the risk that a single catastrophe would lead to extinction, managers propose to restore multiple "insurance" populations on islands currently unoccupied by these species to increase their range and overall numbers.