The lovely Scarlet-backed Flowerpecker with its short tail measures only 8.5 cm.
The male has glossy blue-blackish wings and a bright red streak down its back from its crown to its tail coverts.
The female (4th & 5th photo) is much paler with red only on the rump.
The female is predominantly olive-green and can be distinguished from other flowerpeckers by her bright red rump that is often visible when hovering and foraging. 
The juvenile has plumage similar to the female but has an orange bill and lacks the bright red rump.
It is found in a number of countries throughout South and East Asia.

Sungei Buloh Wetland Reserve, Singapore, 25 October 2022