The expedition began with the goal of exterminating domestic rabbits that had been introduced to Laysan island by the guano industry in 1902. Since that time, the rabbits had devoured Laysan's vegetation and led to the extinction of several endemic species. The rabbits were eventually eliminated on Laysan, and the crew witnessed the extinction of the Laysan honeycreeper (apapane). Throughout the expedition, new species were discovered and named, and unique specimens were captured and returned to laboratories for further study. Over 100 archaeological sites were found, including ancient religious sites and prehistoric settlements on Nihoa and Necker Island.