Hawaiian honeycreepers are among evolution’s greatest examples of adaptive radiation, which occurs when one species diversifies into many to exploit a range of resources. But since the arrival of the first humans—and especially since Europeans and Americans showed up and introduced mosquitoes—two-thirds of the islands' honeycreepers have gone extinct. Only 17 species survive, including the Kiwikiu, a small olive-green passerine that wears a streak of yellow eyeliner and lives in the forests on the windward slopes of the Haleakalā volcano on Maui. Now with only 150 Kiwikiu left and dire predictions that these birds will be wiped out within six years, scientists and officials are mounting another desperate effort to save the species. The problem is that not everyone agrees on the best plan, and the clock is ticking. “We’re trying to make use of all the expertise available to us in order to make the best possible decisions at this point,” says David Smith...