Thick-billed Flowerpecker (Dicaeum agile) - HBW 13, p. 370

Taxonomy: Fringilla Agilis Tickell, 1833, Borabhúm and Dolbhúm, Bengal, east India.
Shares tongue morphology with D. aureolimbatum, D. bicolor and D. celebicum. Poorly known N Natuna race bungurense of D. everetti (known only from the type specimen) possibly belongs with present species. Geographical variation complex, involving bill shape and various plumage characters (particularly colour of dorsal surface, pale spots on rectrices and ventral streaking), and with mosaic pattern of distribution among races. Philippine races (striatissimum, affine and aeruginosum) sometimes considered to represent a separate species; other races fall into two further groups, one in W (nominate and zeylonicum) and the other from NE India and SE Asia S to Sundas (remaining races), these groups possibly representing two additional species; moreover, finschi is perhaps sufficiently distinctive to be considered a separate species. Other proposed races are deignani (described from Kohima, in Assam) and separabile (from Dalat, in C Vietnam), both synonymized with pallescens, and remotum (from Negri Sembilan, in Peninsular Malaysia), considered indistinguishable from modestum. Eleven subspecies currently recognized.