Why have control efforts sometimes failed to reduce the overall continental population of Queleas?

Answer

Attempts to eliminate them scatter the flocks, causing them to breed elsewhere with less competition

Large-scale culling can inadvertently trigger metapopulation dynamics by scattering massive flocks, leading to breeding success in new areas, thereby maintaining or increasing the total continental count.

Why have control efforts sometimes failed to reduce the overall continental population of Queleas?
birdfaunaOriginquelea