Large flocks of European Starlings, typical of this species can be beneficial to agriculture by controlling invertebrate pests; however, starlings can also be pests themselves when they feed on fruit and sprouting crops. Common starlings may also be a nuisance through the noise and mess caused by their large urban roosts. Introduced populations in particular have been subjected to a range of controls, including culling, but these have had limited success, except in preventing the colonisation of Western Australia.
The Brown Thrasher is omnivorous, which has a diet that includes insects, berries, nuts and seeds, as well as earthworms, snails, and sometimes lizards and frogs. Across seasons and its breeding range, it was found 63% of stomach contents were made of animal matter, the remaining 37% being plant material. During the breeding season, the diet consists primarily of beetles, grasshoppers, and other arthropods, and fruits, nuts and seeds. More than 80% of the diet of brown thrasher from Illinois is made of animal matter, about 50% being beetles. In Iowa, about 20% of the summer diet was found to consist of grasshoppers. By the late summer, it begins to shift towards more of a herbivore diet, focusing on fruits, nuts, seeds, and grains, 60% of the food in Illinois being fruits and seeds. By winter, the customary diet of the brown thrasher is fruit and acorns.