This native Hawaiian bird was declared "extinct in the wild" in 2002 when the last two known wild individuals disappeared. Some birds remain in captivity, and between 1993 and 1999, more than 40 birds were hatched in a captive breeding program. The birds were released into a lightly managed habitat and closely monitored, but releases were abandoned in 1999 because of increasing mortality. A reintroduction plan is being developed, but about 75 Hawaiian crows would be needed for the plan to work. The reasons for the bird's extinction is not fully understood, but researchers speculate that an introduced disease, such as avian malaria, might have played a significant role in the species' decline.