In February, the male Nile Valley Sunbird assumes his nuptial plumage which he displays in flamboyant fashion. In winter both sexes look alike, tiny, only 9 to 10 cm long, pale grey above and washed-out yellow below, with a long, slender and slightly down-curved bill.
By February the male is transformed into a glossy green extrovert with a brilliant sulfur-yellow belly and long tail streamers that add about an extra five centimetres to his length.
Once transformed, he will be puffing up and parading his newfound finery and courting his duller mate. The display includes a hovering, accompanied by body rocking and wing-whirring.
BirdLife International 2004. . Downloaded on 25 July 2007.