Red-billed quelea closely related to the fodies ("Foudia"), a genus of six or seven species that occur on the islands of the western Indian Ocean. These two genera are in turn the sister clade to the Asian species of the genus "Ploceus". The following tree represents current insight of the relationships between the species of "Quelea", and their closest relatives. Interbreeding between red-billed and red-headed queleas has been observed in captivity. The red-billed quelea is a small sparrow-like bird, approximately long and weighing , with a heavy, cone-shaped bill, which is red (in females outside the breeding season and males) or orange
Red-billed quelea from northern and central Sudan and central Ethiopia in May and June, to breed in southern Sudan, South Sudan, southern Ethiopia and northern Kenya, moving back north from August to October. In southern Africa, the total population of the subspecies "Q. quelea lathamii" in October converges on the Zimbabwean Highveld. In November, part of the population migrates to the northwest to northwestern Angola, while the remainder migrates to the southeast to southern Mozambique and eastern South-Africa, but no proof has been found that these migration cohorts are genetically or morphologically divergent. The red-billed quelea is regarded as the most numerous