The birds with a alack head in Vietnam could be:
1/ Black-headed Sibia
Heterophasia desgodinsi
Mi đầu đen
2/ Black-headed bunting
(Emberiza melanocephala)
Sẻ đồng đầu đen
3/ Chat (Saxicola):
Siberian stonechat or Asian stonechat (Saxicola maurus),
Amur stonechat (Saxicola stejnegeri) or Stejneger's stonechat