The Aztec Ritual Offering Against Drought - In this illustration three priests carry offerings and walk beside a stream into which are cast decapitated birds. The priests wear necklaces of green stones or chalchiuitl (jade) and wear their long hair tied with three red rings. Two of the priests wear a headdress of flowers. All the men carry bags or pouches. One carries a staff and an incense burner with Aztec incense or copal (or copalli, a dried resin from various trees), another blows a conch shell, and the third wrings the neck of a bird. A flowering cactus rests on an island in the middle of the water. The decapitated doves were a ritual offering against drought. The conch shell was often used in religious ceremonies.