The Olive Sunbird is a species of sunbird

Sunbird

The sunbirds and spiderhunters are a family, Nectariniidae, of very small passerine birds. There are 132 species in 15 genera. The family is distributed throughout Africa, southern Asia and just reaches northern Australia. Most sunbirds feed largely on nectar, but also take insects and spiders,...

 found in a large part of Africa

Africa

Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

 south of the Sahel

Sahel

The Sahel is the ecoclimatic and biogeographic zone of transition between the Sahara desert in the North and the Sudanian Savannas in the south.It stretches across the North African continent between the Atlantic Ocean and the Red Sea....

. It prefers forested regions, and is absent from drier, more open regions such as the Horn of Africa

Horn of Africa

The Horn of Africa is a peninsula in East Africa that juts hundreds of kilometers into the Arabian Sea and lies along the southern side of the Gulf of Aden. It is the easternmost projection of the African continent...

 and most of south-central and south-western Africa. It is sometimes placed in the genus Nectarina.

The western subspecies (roughly west of the Great Rift Valley

Great Rift Valley

The Great Rift Valley is a name given in the late 19th century by British explorer John Walter Gregory to the continuous geographic trench, approximately in length, that runs from northern Syria in Southwest Asia to central Mozambique in South East Africa...

) are sometimes split as the Western Olive Sunbird, Cyanomitra obscura, in which case Cyanomitra olivacea becomes the Eastern Olive Sunbird