Trichomonas spp. Prevalence in Nestling Peregrine Falcons (Falco peregrinus) in Kentucky, USA, 2005-23, and Effects on Survival.

The Peregrine Falcon (Falco peregrinus) is a species of conservation interest throughout much of eastern North America, and management efforts for the species are widespread. Peregrines are at risk for exposure to Trichomonas spp. because of their tendency to take pigeons and doves (Columbiformes) as prey. We investigated the prevalence of Trichomonas spp. in wild nestling Peregrine Falcons banded in nests in Kentucky, USA. We tested throat swabs collected from 266 Peregrine Falcons during 2005-23. A total of 21 birds tested positive for Trichomonas spp.; none of the falcons that tested positive were resighted as adults. We treated a subset of nestlings for Trichomonas spp. infection, including two in the nest (without removal), two nestlings temporarily removed from the nest for treatment, and 10 placed with wildlife rehabilitators for treatment. Rehabilitated nestlings were released at an age of ≥75 d. However, we did not confirm any benefits to survival from treatment. Trichomonosis may hinder Peregrine Falcon nestling survival in certain areas, especially urban locations.