Styan's Grasshopper Warbler

Styan's grasshopper warbler (Helopsaltes pleskei), also known as Pleske's grasshopper warbler and Taczanowski's warbler, is a species of Old World warbler in the family Locustellidae. It breeds in eastern Siberia to Korea, Kyushu and Izu Islands; wintering in South China. Its natural habitats are temperate shrubland, subtropical or tropical dry shrubland, and swamps. It is threatened by habitat loss. Its name recognises the naturalist and collector, Frederick William Styan. (Wikipedia, general species account).

This species belongs to a group of small, active songbirds that generally search foliage, stems or ground cover for insects and other small invertebrates. Many are easier to detect by voice than by sight, particularly in dense vegetation, and closely related forms may require calls, season and range for confident identification. These are group-level ecological notes, not Vietnam-specific breeding measurements (general warbler ecology).