Gadwalls (Anas strepera) hatched at Mono Lake, California, exhibit two types of severe foot damage, one manifested by the formation of hard white nodules on the plantar surface, the other by necrosis, which results in deformed and eroded webs and, in extreme cases, loss of podotheca and toes. Unknown in Gadwalls elsewhere or in other waterbirds at Mono Lake, these conditions may be evident in ducklings only three weeks old. They presumably stem from infections incurred after ducklings abrade their feet on the harsh lake substrate. The causative agent(s) is unknown.