Ashy-throated Warbler Phylloscopus maculipennis      photos Sid Francis

Very small - yellow underside (can be worn/faint) - grey face/throat (can be faint) - splays tail, light (yellow) outers -  - small bill one of the smaller warblers - coronal stripe and wing bar but not the most distinctive features. 

Similar species - Buff-barred also splays tail but with pure white outers - can overlap habitat but generally buff-barred breeds higher - yellow undersides and grey face are usually enough to make an easy distinction

Habitat - typical mixed middle altitude forest from around 2000 to 3000m

Vocalizations - indistinct high pitched single note call - has song but can be difficult to hear with no good recordings of Chinese birds on xeno-canto

Call here     Sid Francis iNaturalist