In 1974, 51 debilitated lesser flamingos (Phoeniconaias minor) were easily captured at Lake Nakuru, Kenya. Nineteen (37%) of these had extensive mycobacterial lesions. Two years later it was difficult to locate any debilitated flamingos and no evidence of mycobacterial infection was found. Possible reasons for the high prevalence of mycobacteriosis in the 1974 collection are discussed.