The Mauritius olive white-eye Zosterops chloronothos is the least known of the eight threatened terrestrial bird species remaining on the island of Mauritius. The olive white-eye has declined drastically in numbers and distribution since 1975. Surveys carried out between 1998 and 2001 estimated that 93–148 pairs remained within an area of less than 25 km2. Most areas that held olive white-eye territories in 1975 supported considerably fewer territories in 2001. This decline is thought to have primarily been the result of deforestation and degradation of native habitat and intense nest predation by introduced mammals. Declines have been more severe in areas dominated by native vegetation than they have been in areas that contained substantial amounts of exotic Cryptomeria and Pinus. The continued decline of the Mauritius olive white-eye is of critical concern and immediate species-specific conservation management is required for its survival.