What dietary shift causes the Red-billed Quelea to become an agricultural pest?

Answer

Shifting focus to cereal grains when near cultivated lands

While these birds primarily consume grass seed, when large numbers congregate near cultivated lands, they shift their focus to cereal grains like wheat, sorghum, and millet, often devastating harvests.

What dietary shift causes the Red-billed Quelea to become an agricultural pest?
speciesbirdendangeredwildlifequelea