The fork-tailed sunbird (Aethopyga christinae) is a species of bird in the Nectariniidae family. It is found in China, Hong Kong, Laos, and Vietnam. Its natural habitat is subtropical or tropical moist lowland forests. These small birds, with decurved bill, call a soft and frequent "zwink-zwink" and a metallic trill. The bird appears in the most commonly used postal stamp of Hong Kong.