Red-billed quelea is sometimes called "Africa's feathered locust". The usual pest-control measures are spraying avicides or detonating fire-bombs in the enormous colonies during the night. Extensive control measures have been largely unsuccessful in limiting the quelea population. When food runs out, the species migrates to locations of recent rainfall and plentiful grass seed; hence it exploits its food source very efficiently. It is regarded as the most numerous undomesticated bird on earth, with the total post-breeding population sometimes peaking at an estimated 1½ billion individuals. It feeds in huge flocks of millions of individuals, with birds that run out of food at
Red-billed quelea Three subspecies are recognised. In the field, these are distinguished by differences in male breeding plumage. Formerly, two other subspecies have been described. "Q. quelea spoliator" was described by Phillip Clancey in 1960 on the basis of more greyish nonbreeding plumage of populations of wetter habitats of northeastern South Africa, Swaziland and southern Mozambique. However, further analysis indicated no clear distinction in plumage between it and "Q. quelea lathamii", with no evidence of genetic isolation. Hence it is not recognised as distinct. "Q. quelea intermedia", described by Anton Reichenow in 1886 from east Africa, is regarded a synonym of subspecies