A species of passerine bird in the flowerpecker family Dicaeidae. Sexually dimorphic, the male has navy blue upperparts with a bright red streak down its back from its crown to its tail coverts, while the female and juvenile are predominantly olive green. Originally described by Linnaeus in 1758 in the 10th edition of his work Systema Naturae, with the binomial name of Certhia cruentata among the treecreepers. It has been observed feeding on the figs of Ficus ﬁstulosa and F. grossularoides. The scarlet-backed flowerpecker weaves its pouch-shaped nest hanging from a branch high up in a tree. The nest has a side entrance, typical for those of the flowerpecker family.