Certain bird species such as blackbirds, pheasants, partridges, sparrows and starlings target the sweet grapes during the ripening period from August onwards and can cause a considerable reduction in yield. Bird plagues in vineyards were already described in antiquity and are still a problem worldwide. In spring and summer, however, they can be desirable as insectivores and thus as beneficial insects. In extreme cases, very large flocks of up to 10,000 birds and more can occur; this is especially true of the starling. If such a flock of birds settles on a vineyard, it is "harvested" in a short time. As a negative side effect, damaged or pecked berries encourage the penetration of microorganisms such as bacteria and fungi and thus the occurrence of grape rot.