About Phylloscopus orientalis (C.L.Brehm, 1855)
Eastern Bonelli's warbler (Phylloscopus orientalis), sometimes called the Balkan warbler, is a species of warbler in the leaf warbler genus Phylloscopus. It was previously classified as the eastern subspecies of a broader, combined "Bonelli's warbler" species, but modern taxonomic revisions now treat this group as two separate species: Western Bonelli's warbler (Phylloscopus bonelli), which breeds in southwestern Europe and northern Africa, and Eastern Bonelli's warbler (Phylloscopus orientalis), which breeds in southeastern Europe and Asia Minor. The breeding ranges of these two species do not overlap. While their appearance and songs are very similar, their calls are completely different, and they also show marked differences in their mtDNA sequences. This species is migratory, and spends the winter in sub-Saharan Africa. It is a rare vagrant in Northern Europe. Eastern Bonelli's warbler is a small passerine bird that inhabits forest and woodland. It lays four to six eggs in a nest built on the ground. Like most warblers, Eastern Bonelli's warbler is insectivorous. Adults have a plain grey-green back, green-toned rump and wings, and whitish underparts. They have a small pointed bill and brown legs. As with most warblers, the sexes are identical in appearance. Compared to Western Bonelli's warbler, Eastern Bonelli's warbler lacks the brownish tinge on its upperparts, and sometimes has a greenish tinge instead. The song of Eastern Bonelli's warbler is a fast monotone trill, which is only slightly different from the song of Western Bonelli's warbler, and also has some similarity to the song of the wood warbler. The call of Eastern Bonelli's warbler is a hard chup, which resembles the call of a crossbill or a house sparrow, and is completely different from the disyllabic hu-it call of Western Bonelli's warbler. The genus name Phylloscopus comes from Ancient Greek: phullon means "leaf", and skopos means "seeker" (from skopeo, meaning "to watch"). The specific epithet orientalis is Latin for "eastern". The English common name honors the Italian ornithologist Franco Andrea Bonelli.
