sunbird, common name for tropical, Old World birds, including more than one hundred species in the family Nectariniidae. Like the unrelated New World hummingbirds, to which sunbirds are often compared, sunbirds have long and slender, highly curved bills, tube-shaped tongues, and feed primarily on nectar and small insects. However, they perch when feeding rather than hovering as the hummingbirds do. They are typically small birds, with the largest, the great sunbird ( Dreptes thomensis ) reaching a maximum length of 81/2 in. (22 cm), and are native to forest and brush throughout Africa, Asia, and the South Pacific. Some common species are the variable sunbird ( Cinnyris venustus ), the purple sunbird ( Nectarinia asiatica ), and the golden-winged sunbird ( N. reichenowi ). The males of most species are brightly colored, with metallic, sometimes velvety, plumage. Out of breeding season, the males tend to take on the duller female plumage. Sunbirds may change their feeding grounds during the nonbreeding season but are not particularly migratory. They are not very gregarious, and males tend to be aggressive, especially during breeding season. Sunbirds build a characteristic purselike, hanging nest, into which the female deposits her two, rarely three, white or pale blue, variously spotted or striped eggs. Two unrelated Madagascan species in the genus Neodrepenis are known as false sunbirds, and are easily confused with the sunbirds, which they resemble in habits, habitat, diet, and somewhat in appearance. They are, however, slenderer and shorter-legged, with more markedly down-curved bills. The related spider hunters, of the genus Arachnothera, are members of the true sunbird family and are found in Asia. They lack the metallic coloration of their sunbird relatives, and the sexes are more alike, both being dull greens, browns, or yellows. Spider hunters (e.g., the little spider hunter, A. longirostris ) feed largely on insects and spiders. Their singular cup-shaped nest is built on the bottom of a broad leaf and attached firmly by cobwebs and plant fibers, which the bird sews and knots together. Both sexes build the nest and share incubation of the two to three eggs laid per clutch. Sunbirds and their relatives are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Passeriformes, family Nectariniidae.