# UKBirds

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## Greenish Warbler

### Phylloscopus trochiloides

The Greenish Warbler (Phylloscopus trochiloides) are widespread leaf warblers throughout their breeding range in northeastern Europe and temperate to subtropical continental Asia. This warbler is strongly migratory and winters in India. It is not uncommon as a spring or early autumn vagrant in Western Europe and is annually seen in Great Britain. In Central Europe large numbers of vagrant birds are encountered in some years; some of these may stay to breed, as a handful of pairs does each year in Germany.
Like all leaf warblers, it was formerly placed in the "Old World warbler" assemblage, but now belongs to the new leaf-warbler family Phylloscopidae.
This is a typical leaf warbler in appearance, grayish-green above and off-white below. The single wing bar found in the southern and western populations distinguishes them from most similar species (except Arctic Warbler P. borealis). It is slightly smaller than that species and has a thinner bill, without a dark tip to the lower mandible. A latitude-based analysis of wintering birds indicated that more northerly P. trochiloides are smaller, i.e. this species does not seem to follow Bergmann's rule.
Its song is a high jerky trill, in some populations containing a sequence of down- and more rarely up slurred notes.
It breeds in lowland deciduous or mixed forest; non-breeding birds in the warmer parts of its range may move to montane habitat in summer. Individuals from southeast of the Himalayas are for example quite often seen in Bhutan during the hot months, typically in humid Bhutan Fir (Abies densa) forest up to about 3,800 meters ASL or more, but they do not breed there and return again to the adjacent subtropical lowlands in winter.
The nest is on the ground in low shrub. Like its relatives, this small passerine is insectivorous.