In the Amazon forest, many herbivores including macaws regularly pop by clay licks to obtain micronutrients like sodium and magnesium. These minerals supplement their low-salt, plant-based diets.
Geophagy (the eating of clay) is also thought to neutralise plant toxins, get rid of parasites, and relieve diarrhoea.
Ecotourists are fond of visiting mineral licks to see mixed flocks of colourful birds concentrated in one place.