We collected 153 northern bobwhites (Colinus virginianus) over a 10-mo period from Tall Timbers Research Station near Tallahassee, Florida, USA. Five species of gastrointestinal helminths were encountered commonly (>30% prevalence): Cyrnea colini, Raillietina cesticillus, R. colinia, Heterakis isolonche, and Trichostrongylus tenuis. Other helminths included Brachylaima sp., Rhabdometra odiosa, Mediorhynchus papillosis, Cheilospirura spinosa, Dispharynx nasuta, Gongylonema ingluvicola, and Tetrameres pattersoni. During the intervening 15 yr since the last year-round study of this population of birds, C. spinosa and T. pattersoni have declined markedly, and Strongyloides sp. probably has become extinct locally. Prevalence and intensity seem more likely to fluctuate in parasite species that have complex life cycles.