Are there two subspecies of Red-billed Quelea, Quelea quelea, in southern Africa?

Abstract

Two subspecies of the Red-billed Quelea, Quelea quelea lathamii and Q. q. spoliator, have been described from southern Africa on the basis of differences in dorsal colouration in non-breeding plumage, but the validity of spoliator has often been challenged. We examined museum specimens of both subspecies, including paratypes of spoliator, and recorded plumage characters of breeding and non-breeding queleas in the wild. These data suggest that 'typical' lathamii and spoliator merely represent two extremes of a continuous variation in colour, with the majority being intermediate. Significantly, breeding males whose plumage types span the range between spoliator and lathamii occur together in the same colonies. Furthermore, variation in male nuptial colouration, which has provided the basis for distinguishing the subspecies of Red-billed Queleas elsewhere in Africa, shows no association with differences in dorsal plumage colour. We also present data on the timing of breeding of the two taxa which suggest that reproductive isolation sufficient to maintain two separate subspecies within southern Africa is unlikely to occur. We conclude, therefore, that because spoliator individuals cannot be reliably separated from lathamii on morphological criteria and, because both forms are likely to breed in the some places at the some times, the subspecies spoliator does not reflect any meaningful phylogenetic division. The Red-billed Quelea is therefore represented by Q. q. lathamii alone in southern Africa.