SELF-MEDICATION. “The consumption of natural substances that help an organism combat parasitic infection has been observed in a number of vertebrate and invertebrate species…anting behavior in birds refers to the act of rubbing crushed ants, plants, millipedes or other substances onto feathers and skin to exploit the anti-parasitic properties of these substances.”
http://en.m.wikipedia.org/wiki/Behavior-altering_parasites_and_parasitoids