Crow Unhappy the Treat Box is Empty - 5 Stages of Grief 

On one occasion when recording the crow doing the puzzle box, it by chance opened the food-containing compartments first. Then it left with the food and came back to finish the box. Except all the remaining compartments were empty, much to the crow's displeasure. I feel like it's displaying the 5 stages of grief. Denial: the crow circles the box. Anger: pecking and dragging the box. Bargaining: nibbling the box. Please dispense more food. Depression, and acceptance: Checks the compartments one more time. Decides to leave.
Don't worry, crow got lots of nice snacks after this.