The Greenish Warbler is a small bird with clear olive-green upperparts and one light bar on the wings (the subspecies plumbeitarsus has two light wing bars); underparts are grayish-white sometimes with slight buffy or yellowish tinge, but never clear yellow. It is distinguished from Chiffchaff by the bright color; from Yellow-browed and Hume's Warblers by the large size and by the absence of pale edges on tertials. In autumn plumage adult birds is greener above especially on the rump; upperparts are more yellow than in spring. Juveniles in first plumage are similar on adults but have more brown upperparts; the plumage is more loose. The autumn juveniles resemble adults but greener above and more yellow below. The wing form: the 1st primary projection is 7-12 mm; the 2nd primary is equal on 7th or 8th, probable between 6th and 7th or between 8th and 9th; the 3rd, 4th and 5th primaries are about equal length, have the notch on outer web, and form the wing top; the 6th primary doesn't have notch or it is slight visible. Weight 5-9 grams, length 10-13, wing 5,5-6,7, wingspan 17-20 cm.
The Greenish Warbler breeds only in the mountains of South-Eastern and Eastern Kazakhstan (Tien Shan, Altai, Dzhungarsky Alatau). Also the isolated nesting in the Karkarala and Bayanaul uplands is known. But on migration the Greenish Warbler occurs throughout, especially in large number it occurs in all parts of south and east of Kazakhstan. The detailed distribution in Kazakhstan please see in the chapter "Subspecies".
The Greenish Warbler is common, in places abundant breeding migrant. It inhabits the spruce, spruce-fir, larch and pine forests, the mixed forests and sometimes birch groves on up to 1900 m in Altai and 2700-2800 m in Tien Shan. On migration it visits the deciduous forest, reed-beds, bush thickets, forest-belts and tall weed thickets. It appears in mid-April – early May singly or in small groups up to two-three dozen birds; often with other Leaf Warblers; majority of the birds migrate in May; latest spring migrants recorded in early June. It breeds in separate pairs on 35-100 m from each other. The well hidden nest is built on the ground under the stone, between the stones, in the moss tussock, dead bark or dry twigs pile. Only female builds nest from the moss and dry grass and lines it with hair, feathers, and very rare only with grass bast. Clutches of 3-7 eggs is in end May – early July. Only female incubates for 12-13 days. Both parents feed juveniles, which fledge at 12-14 days old, in mid-July – early August. One brood per season, repeated breeding after losing of the first nest is not excluded. Autumn migration begins in end July - early August, majority of birds migrate in September, latest autumn migrants recorded in early October, and even in early November (at once 4 December 1959).
 Phylloscopus trochiloides viridanus (Blyth, 1843)Description. Upper parts are lighter, less clean-green, more brownish-green than on plumbeitarsus. The light tips of upper wing greater coverts form one wing bar, less contrast than on plumbeitarsus. |
 Phylloscopus trochiloides plumbeitarsus (Swinhoe, 1861)Description. Upper parts are darker and more clean-green, less brownish-green than on viridanus. Light tips of upper wing median and lesser coverts form the two wing bars, first of them is more contrast than on viridanus. |
В.К.Рябицев. "Птицы Урала, Приуралья и Западной Сибири". Екатеринбург, Изд-во Уральского университета, 2000. Gavrilov E. I., Gavrilov A. E. "The Birds of Kazakhstan". Almaty, 2005. Э.И.Гаврилов. "Фауна и распространение птиц Казахстана". Алматы, 1999. А.Ф.Ковшарь "Певчие птицы". Алма-Ата, "Кайнар", 1983.