Sunbirds drink like hummingbirds without sharing their ancestry
Nectariniidae sunbirds and spiderhunters—152 species in sixteen Old World genera—wear curved bills and, in males, iridescent blaze from Africa through Asia to Australasia. Nectar leads the diet, insects feed chicks, and long tubular flowers simply get pierced at the base.
Sunbirds are the Old World's answer to hummingbirds, but the two are only distantly related. Both evolved slender curved bills and tube-shaped tongues with brushy tips for drinking nectar, as did Australia's honeyeaters. Most sunbirds perch rather than hover, and when a flower is too long and narrow they simply pierce it near the base and sip from the nectaries. Short wings give them fast, direct flight, and insects and spiders supply protein, especially for chicks.
The flowers have evolved in return. Sunbird-pollinated blooms tend to be long, tubular and red or orange, like hummingbird flowers in the Americas, but sturdier, with a perch where the bird can land. Proteas, aloes, heaths, coral trees and bird-of-paradise flowers all depend on sunbirds for pollination.
The 152 species in 16 genera range from the 5-gram black-bellied sunbird to the 45-gram spectacled spiderhunter. Males are usually larger, longer-tailed and glittering with iridescence, though some lose much of that sheen in the dry months of June to August. The spiderhunters are bigger, drab brown birds with inconspicuous nests, such as small woven cups or long tubes stitched under large leaves, while typical sunbirds hang enclosed, purse-shaped nests bound with spider silk from thin twigs. Birds living high up or far from the equator drop into torpor on cold nights, as Andean hummingbirds do.
Found from Africa to northern Australia and up to 4,900 metres, they mostly breed in the wet season when insects abound. Seven species are threatened, but their unpleasant songs spare them from the cage-bird trade, and the scarlet-chested sunbird is a cocoa pest because it spreads parasitic mistletoe.
Source: Sunbird
