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-headed quelea on recent DNA-analysis, the red-headed quelea forms a clade with the cardinal quelea ("Q. cardinalis"), and this clade is sister to the red-billed quelea "Q. quelea". The genus "Quelea" belongs to the group of true weavers (subfamily Ploceinae), and is most related to "Foudia", a genus of six or seven species that occur on the islands of the western Indian ocean. This clade is sister 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. Red-headed quelea The red-headed quelea ("Quelea erythrops") is a