The shy but vocal Olive Sunbird is a forest denizen by habit, and usually the most commonly encountered sunbird where they occur. They nest throughout spring and summer. Adults weigh only between 8 and 15g, measuring around 15cm long. Not much else is known about these tiny nectar-feeders.
Due to its very specific habitat preferences, the Olive Sunbird has a very restricted distribution in South Africa – here they are found only along the Indian Ocean coast from East London through to northern Kwazulu-Natal, and in a small corner of Mpumalanga around Nelspruit and Barberton. Further north into Africa they are widely distributed through east, central and West Africa. The IUCN lists the species as being of least concern, despite the threat of habitat loss due to uncontrolled deforestation in much of its range.