We were told that parrots in the wild eat more nuts and seeds than fruits. This diet requires them to also eat clay or wood to help digest the poisons that are in some of the seeds and nuts.
These Scarlet Macaws were at a clay lick in the Yasuni National Park. There were 20-30 Scalet Macaws nearby in the trees, and they rotated through the lick in large numbers until they decided as a group that they were done and flew off.