Holly Grant, Project Assistant says:

Hi Elvina, Brown-headed Cowbirds are native birds to North America – you don’t need to do anything. Brown-headed Cowbirds are obligate brood parasites, which means the only way they can breed is by laying their eggs in other birds’ nests. Though the cowbirds have some adaptations which allow them to outcompete some host young, other species have been known to recognize and kick out their eggs or abandon their own parasitized nest, and sometimes cowbird eggs are laid in nests of birds which do not feed a diet that can sustain the cowbird chicks (mostly seeds as opposed to insects that cowbirds need). So, they have their own challenges in survival. One thing that may also help you to know, is that cowbirds have not been implicated in the major decline of any species as of yet – habitat loss and degradation are far and away the biggest threats to birds. If you want to learn more about cowbirds, please feel free to check out this webpage.