Common to locally abundant resident. Breeding male variable as illustrated; breeding female has yellow bill. Non-breeding birds all have red bills. Breeding colonies may be huge, involving tens of thousands, and may cover many hectares of bush. Occurs in flocks and is nomadic when not breeding, mainly in dry thornveld and mixed bushveld. Flocks utter a twittering when flying and nesting. Flying flocks resemble columns of smoke. A serious agricultural pest in some regions.