Cow Whistles
Roll a square piece of paper diagonally around a pencil, forming a cylinder. Remove the pencil and secure with a piece of Scotch Tape. Cut off one end of the cylinder and wrap tape around the end to form a semi-waterproof mouthpiece.
Carefully, trim the other end of the cylinder to form an arrowhead, leaving a small notch in the cylinder.
Fold the arrowhead 90 degrees over the open end of the cylinder. Gently inhale so that the arrowhead vibrates. Take a bow!
Believe it or not, a cow whistle can actually get the critters to stop eating and approach you to investigate. Find a pasture and give it a try!