The Loten’s Sunbird (Cinnyris lotenius), also known as the Long-billed Sunbird, is one of a group of very small Old World passerine birds which feed largely on nectar. Sunbirds will also take insects, especially when feeding young and Loten’s Sunbird is possibly more insectivorous than other sympatric species. Their flight is fast and direct on their short wings. Loten’s Sunbird is a resident breeder that is locally common in forest and cultivation in India and Sri Lanka.
Loten’s Sunbirds are small, only 4.75 to 5.13 inches long. They have long down-curved bills and brush-tipped tubular tongues, both adaptations to their nectar feeding. The bill lengths vary across populations with long bills found on the east of Peninsular India and in Sri Lanka. The adult male is mainly glossy purple with a gray-brown belly. It is similar to Purple Sunbird, but is larger, has a longer sickle-shaped bill, and a different belly color.
The eclipse male has yellow-gray upperparts, darker than Purple Sunbird, and a yellow breast with a blue central streak extending to the belly. The existence of an eclipse plumage in the adult male has however been questioned. The female has yellow-gray upperparts and yellowish underparts, but lacks the faint eyebrow patch.
The call is a buzzy zwick zwick. The song of the male is a long repeated wue-wue-wue… with the last notes accelerated. The males may sing from the tops of bare trees or telegraph wires. Two eggs are laid in a suspended nest in a tree. The bag of webs, bark and caterpillar frass.