Swarms of quelea birds regularly cause considerable damage to crops of sorghum, millet, rice, and other small grains. In recent years this damage has extended to newly introduced crops of wheat and barley.
Quelea attacks occur in east and west African countries, particularly in the drought-prone region of the Sahel. Nearly 1,000 million quelea birds are destroyed each year in Africa by the bombing and poison-spraying of their nightly roosting sites. This costly and hazardous operation often brings about only temporary, local reductions in the numbers of this pest. It seems that there is one very large and highly mobile population of these birds able to concentrate in different areas depending on rainfall. Control efforts have had little detectable effect since the population of birds is rapidly replenished.