Don't Be Fooled

Clue 1:  Those paws have been digging, you can see the grass in-between the toes.

Clue 2:  The position of the aligned legs, covering something up.

Clue 3: That bottom jaw is slightly dropped, there is something in his mouth.

Clue 4:  Just before opening the door and seeing this I could hear a rattling/cracking sound.

Conclusion:  the little hoot is making holes and digging up the lawn to get stones to chew again.

Motive: he loves to wind me up.

Punishment: no idea, not caught him yet.