Small, restless, nectarivorous passerines with slender, pointed, decurved bills. Most species show difference between the plumage of males and females, with the males typically having glisteningiridescent plumage. They have short, rounded wings and show a high flapping rate, moest species are capable of sustained hovering.
They prefer feeding on nectar. The bill is serreted near the tip, enabling 'sawing' into the coroola of the flower from the outside when the nectar cannot be reached 'down the throat' of the flower. The tongue is tubular with a few projections at the tip that suck up and hold nectar by capillary action. It is incredibly long and can be extended out to the same length as the bill. They also eat insects, especially in summer, when breeding, that are gleaned from foiliage, often by hovering, also at spiderwebs, but also by hawking in flight.
They are monogamous and build oval ball-shaped nests, suspended from a branch. They typically lay 2 eggs. Incubation is done by the female alone, the young are fed by both parents. Several subspecies are parasitised by Klaas's cuckoo.

Chalcomitra = copper headband
Cinnyris = shining
Nectarnia = pertaining to nectar

Wikipedia

fatbirder.com