South Africa has 21 species of sunbirds found locally. They all fall under the family Nectariniidae, referring to their preference for feeding on nectar.
Nectar is a sugar-rich food source that is utilised by means of a very long tongue and a specialised bill. The tongue is tubular with some projections at the tongue tip that are used to suck up the nectar, using capillary action. The tongue can be extended, out of the beak, to almost the same length of the beak.
The bill is slender and curved, with a sharp point. The bill has a serrated tip to enable the sunbird to break into the corolla of the flower. Most feeding is done by poking the beak down into the flower.
It is thought that some of the sunbirds are able to slow down their metabolism at night and in very cold weather to save energy. The wings are short and rounded, allowing the sunbirds capable of sustained hovering.
Most species of sunbirds have sexual dichromatism, meaning there is a distinct difference between the male and female colouring and plumage.