The warbling white-eye was described by the ornithologists Coenraad Jacob Temminck and Hermann Schlegel in 1847 from a specimen collected in Japan.

A molecular phylogenetic study published in 2018 found that Z. montanus and several subspecies of Z. japonicus were conspecific, and they were therefore lumped together.

[8] Consequences of its diet include regulation of local insect populations and dispersal of seeds; however, the white-eye's seed-dispersal ability does not seem to be significant in Hawaii.

[9] The warbling white-eye is found in Japan, Korea, Taiwan, eastern China, and the northern Philippines.

[10] In spring 2018 there were several sightings of Japanese white-eyes in Southern California, with confirmed breeding in San Diego County as of 2019.

[14] After subsequent releases and natural range expansion (enlargement of the area it occupies), the white-eye was determined to be the most abundant land bird on the Hawaiian Islands as early as 1987.

[15] It has become a vector for avian parasites that are now known to adversely affect populations of native birds such as Hawaiian honeycreepers, as well as spreading invasive plant species through discarded seeds.

Organisms known to prey upon native Hawaiian avian species include small mammals, like the Polynesian, black, and Norway rats, and the mongoose.

[17] In Hawaii, the warbling white-eye competes with native passerines such as the common 'amakihi, for food (such as nectar and fruit), as well as for space.

Native species need normal juvenile mass and bill length to recover and persist, but for this to happen, food must be restored to former levels.

[20] The determination of the status of native birds is essential; those found to be endangered could possibly benefit from the designation of critical habitat.

[19] In 1980, a program to eradicate the Indian white-eye in California involved mist-netting and shooting the birds, and this proved to be the most successful of the various capture methods explored.