When you are being followed by a parrot, (and you cannot make them sit for very long) the parrots will constantly fly around and destroy your planted crops. This is because their "impact" on the ground is significant enough to destroy crops. I understand a game like Minecraft cannot be realistic in all things, but the landing of a lightweight bird is not like dropping an anvil, and would not cause such impact. It's also VERY disruptive to gardens.