Abstract
It has been demonstrated that helminths are capable of critically impacting the fitness of their hosts. This has typically been shown experimentally through the administration of anthelmintic drugs but are rarely performed on a landscape or host population scale. Here, the anthelmintic fenbendazole (FBZ) was mixed in a supplemental feed and provided to a free-ranging population of Northern bobwhite quail (Colinus virginianus). Abundances of Northern bobwhite and two nematode parasites commonly found infecting Northern bobwhite were monitored and compared to a neighboring untreated population. The Northern bobwhite population receiving the medicated feed grew substantially from 2019 to 2022, while the neighboring site had no change in abundance. The treated population was also substantially greater than the untreated population in 2021 and 2022. Additionally, the treated Northern bobwhite population had substantially lower abundances of the two nematodes. This research provides evidence of the ability of helminth populations to have a negative impact on Northern bobwhite populations and presents a method for reducing helminth abundance in those populations on a landscape scale.