Olive-backed Sunbird

The olive-backed sunbird (Cinnyris jugularis) is one of Singapore’s resident birds.¹ In 2002, it was one of five birds shortlisted by the Nature Society (Singapore) in an unofficial campaign to select Singapore’s national bird.²

The olive-backed sunbird is featured in the Bird Series S$20 currency notes released by the Monetary Authority of Singapore between 1976 and 1984, as well as in the Bird Series Cashcards launched by Singapore Mint in 2001 to commemorate the 25th anniversary of the currency notes.³ It also appears on the S$2 stamp of the 1962 postage stamp series which depicts local flora and fauna.⁴

Description
The olive-backed sunbird belongs to the Nectariniidae or Sunbird family.⁵ Members of this family, with their metallic plumages and slender decurved bills, superficially resemble the hummingbirds of Central and South America,⁶ especially since they are also able to hover when collecting food.⁷ Male olive-backed sunbirds have a distinctive, iridescent bluish-black forehead, throat and upper breast, and bright yellow underparts.⁸ The females have an olive-green plumage on their upperparts and completely yellow underparts.⁹ Juveniles are similar to the females in colour, the olive-green colouration of their upperparts offering camouflage during this vulnerable stage of their lives.¹⁰ Adults are about 11 cm in length.¹¹ Its call is a high-pitched metallic chirp, “cheep, cheep, wheet”, or a high-pitched rising “chee”.¹²

Reproduction
The nest of this species, as with other members of the sunbird family, can be best described as an upside-down pear with a pendulous stalk.¹³ It is often hung on a twig or branch or even unused man-made objects such as a telephone wire or cord,¹⁴ and even hanging laundry in Singapore’s urban setting.¹⁵ The female collects nesting material and builds the nest, while the male will be around nearby, calling or singing.¹⁶ The nest is built using materials such as dead leaves, moss, spiders’ webs, lichens, seed cases and even caterpillar frass.¹⁷ The entrance to the nest is just above the middle of the structure, with a little projecting eave for the parent to perch and enter.¹⁸ Inside, the nest cavity is neatly and cosily lined with materials such as tree cotton or lalang down.¹⁹ They have been known to re-use the same nest up to seven times.²⁰

Olive-backed sunbirds fly low among trees and bushes, making observing them easy.²¹ The locations of their nests in Singapore have been a source of surprise and entertainment to the amateur naturalist, as the olive-backed sunbird seems to like nesting in close proximity to humans.²² Articles and letters written to local media have mentioned these birds nesting in small, spindly plants located along the corridors and balconies of public flats and private apartments,²³ as well as in trees close to windows of houses, and even in bedrooms of large houses.²⁴ Plants where nests have been built include bougainvilleas and figs.²⁵

Olive-backed sunbirds have been recorded to nest all year round, with multiple broods. A clutch of 1–3 mottled, greyish-white eggs are usually laid.²⁶ The parents take turns to look after their young.²⁷ 

Diet
The olive-backed sunbird feeds mainly on nectar extracted from the base of blooms belonging to the Callistemon, Erythrina, Russelia, hibiscus and canna with its curved beak,²⁸ as well as small insects,²⁹ including locustids, ants and spiders. It has also been observed stealing from spiders’ webs.³⁰ It also likes to drink from and bathe in small pools of water that collect in plants such as bird’s nest ferns, alocasias, diffenbachia and anthuriums.³¹

As it feeds on nectar and small fruits, it also serves an ecological role as a pollinator of flowers and spreads seeds it has consumed.³²

Distribution and habitat
This species is found across Southeast Asia and Australasia, from southern China and mainland Southeast Asia to Maluku, New Guinea and north Australia.³³

This is one of the most common sunbirds in Singapore, where six other species of sunbirds have been recorded, all of which are resident.³⁴ The olive-backed sunbird can be found in almost every habitat except denser forests, and is a frequent visitor to gardens, parks³⁵ and coastal areas.³⁶ It is very common and is encountered with at least 90 percent probability in its preferred habitats.³⁷ It seems to have little fear of humans, as shown by its nesting behaviour.³⁸

Variant names
English: Yellow-breasted sunbird³⁹
Malay: Kelicap Biasa; Kĕlicap;⁴⁰ Kelicap pantai⁴¹
Chinese: 黄腹花蜜鸟 (Huang fu hua mi niao)⁴² (“Yellow-bellied nectar bird”)



Author
Eunice Low