All species › Passerines › White-eyes and allies › Warbling White-eye
Warbling White-eye | Zosterops japonicus
Japanse brilvogel | Anteojitos japonés
It is in every garden, park and woodland edge on Hawaii, and usually ten at a time: a green bird of ten centimetres with a white ring around the eye. The first birds were released on Oʻahu in 1929; it is now one of the most numerous land birds of the archipelago, from the coast up to the tree line at over three thousand metres.
Voice
The sound heard all day is a thin, plaintive tseeee rising slightly at the end, with which the members of a party keep track of one another; once known, it is everywhere. The song is a high, fast, run-on twittering of thin notes, two to four seconds long, usually from a high branch and mainly from February to June. On taking off the bird gives a short dry chip. In Japan it is the 'mejiro', 'white eye', and it was kept as a cage bird for centuries for exactly that song.
Recording: Bo Shunqi 薄顺奇 — CC BY-NC-SA 4.0 · Shanghai Zoo, Shanghai Shi, China · xeno-canto
Identification
Ten to a little over eleven centimetres and eight to fourteen grams: after the honeycreepers the smallest land bird of the islands. Crown, back and tail are yellow-green, the throat and undertail coverts bright yellow, the belly dirty white and the flanks a warm buff-brown. A small black line runs between bill and eye, which sharpens the white ring further; the legs are blue-grey. Male and female cannot be told apart; young birds are duller, with a narrower and less closed ring. The shape is short and rounded, with a short tail, and while feeding the bird hangs upside down as often as it perches upright.
Confusion species
Hawaiʻi ʻAmakihi (Chlorodrepanis virens) is the one real confusion species: also yellow-green and about the same size, but with a clearly decurved bill, a black mask around the eye and no white ring; its call is a short nasal tsweet. The Japanese Bush Warbler keeps to the same scrub but is brown, larger and stays in the lowest layer. In the canopy of native forest parties of white-eyes and ʻamakihi drift through one another; the calls separate them sooner than the plumage does. Young honeycreepers are greener on the back and never show that sharply drawn white ring.
Habitat
From flowering street trees and gardens in Honolulu to ohia and koa forest high on the volcanoes: there is hardly any vegetated ground on the islands where it is missing. It works the outermost twigs and the blossom, and uses introduced plantings just as readily as native forest. The range runs from sea level to about three thousand one hundred metres, as far as the last trees stand. Only bare lava, open grassland and the highest crater slopes are left empty.
Where the bird is most often found, arranged by the USNVC — the vegetation classification of the United States and Canada — and CMECS for sea and coast.
Range and movements
Its own range lies in Japan, Korea, Taiwan and southern China, outside the guide area; only Hawaii appears on it. From 1929 the agriculture board released birds on Oʻahu, and further releases followed up to 1937, among them two hundred and fifty-two birds on the island of Hawaii in June 1937. After that it moved fast: Kauaʻi in the early 1930s, Lanaʻi around 1933, Niʻihau by 1947, Molokaʻi by 1948 at the latest, Maui from the 1950s, and on Kahoolawe too it is now among the commonest birds. For the island of Hawaii about 1.3 million birds were calculated in the surveyed forest for 1977–1979, and for Kauaʻi around 1970 two hundred and fifty-six thousand. Since the 1980s numbers have fallen on several islands.
- Resident
Where and when to look
Stand by a flowering tree — a coral tree, a eucalyptus in bloom, a bottlebrush in a garden — and wait for a party to drop in; it seldom stays longer than a minute. The most useful sign is not the sight but the sound: that thin calling shifting slowly through the crowns. In any park in Honolulu it takes a quarter of an hour.
Conservation
Least Concern (LC), and by far the most numerous forest bird on the islands, although numbers have fallen since the 1980s on Oʻahu, Kauaʻi and the island of Hawaii. It is neither managed nor controlled there. Research on the islands links it to the spread of the seeds of introduced plants, to the transmission of avian malaria, and to competition for nectar and insects with native honeycreepers.
Scientific name
Zosterops japonicus | Temminck; Schlegel, 1845
Temminck and Schlegel described the species in 1845 in the Fauna Japonica as Zosterops japonicus; the name has stood unchanged ever since, which is why author and year are not in parentheses. The genus Zosterops was introduced by Vigors and Horsfield in 1827, from Greek zoster, 'girdle', and ops, 'eye' — the ring around the eye. japonicus means 'of Japan'. Mees restricted the type locality in 1957 to Decima near Nagasaki: Dejima, the artificial island that held the Dutch trading post and from which the material for that book was shipped to Leiden.