The Marico sunbird exhibits clear sexual dimorphism. The male has metallic shimmering green upperparts and throat, a greyish belly and distinct breast bands in red and blue. The female is more discreetly coloured in grey-brown tones with blurred streaks on the pale yellow underside. Both sexes have a long, downward-curving bill that is adapted for drinking nectar. The bird thrives best in dry acacia savannah, in open woodlands and riverine vegetation. It is also often seen in gardens and parks. It feeds mainly on nectar but also catches insects and spiders, especially during the breeding season to feed the young. The female builds a pear-shaped nest of plant material and cobwebs, which is often camouflaged with bark or droppings. She incubates the eggs alone for about two weeks.