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 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