Red-billed quelea far above the bill, and the underparts may have a pink wash. There is much variability within subspecies, and some birds cannot be ascribed to a subspecies based on outward appearance alone. Because of interbreeding, specimens intermediate between subspecies may occur where the ranges of the subspecies overlap, such as at Lake Chad. The female pin-tailed whydah could be mistaken for the red-billed quelea in non-breeding plumage, since both are sparrow-like birds with conical red-coloured bills, but the whydah has a whitish brow between a black stripe through the eye and a black stripe above. Flying flocks make a distinct
Red-billed quelea quelea needs of precipitation to breed, with nest building usually commencing four to nine weeks after the onset of the rains. Nests are usually built in stands of thorny trees such as umbrella thorn acacia ("Vachellia tortilis"), blackthorn ("Senegalia mellifera") and sicklebush ("Dichrostachys cinerea"), but sometimes in sugar cane fields or reeds. Colonies can consist of millions of nests, in densities of 30,000 per ha (12,000 per acre). Over 6000 nests in a single tree have been counted. At Malilangwe in Zimbabwe one colony was long and wide. In southern Africa, suitable branches are stripped of leaves a few days