The sunbirds and spiderhunters are very small passerine birds which feed largely on nectar, although they will also take insects, especially when feeding young. Flight is fast and direct on their short wings.
The sunbirds have counterparts in two very distantly related groups: the hummingbirds of the Americas and the honeyeaters of Australia. The resemblances are due to convergent evolution due to the similar nectar-feeding lifestyle. Most sunbird species can take nectar by hovering like a hummingbird, but usually perch to feed.
Sunbirds are tropical species, with representatives from Africa to Australasia; the greatest variety of species is in Africa, where the group probably arose. Most species are sedentary or short-distance seasonal migrants. Like the hummingbirds, sunbirds are strongly sexually dimorphic, with the males usually brilliantly plumaged in metallic colours. Sunbirds have long thin down-curved bills and brush-tipped tubular tongues, both adaptations to their nectar feeding. They are monogamous and often territorial. Up to three eggs are laid in a purse-shaped suspended nest. The female builds the nest and incubates the eggs alone, although the male assists in rearing the young after hatching.
The Spiderhunters, of the genus Arachnothera, are distinct in appearance from the other members of the family. They are typically a drab brown colour, with strong down-curved beaks. They build cup-shaped nests, and both sexes help to incubate the eggs.
Like hummingbirds, and unlike other birds, sunbirds drink by using protrusible grooved or trough-like tongues..