It was the same string they had used to fly their kite.
The string had held the kite to the branch for a long time.
Then one day North Wind came again and tried to carry it away.
He puffed and puffed, and at last the branch let go of the string.
The kite flew up in the air and far away, but the string dropped to the ground under the oak tree.
There Bunny found it, and he tied the string around the acorn.
Then he scampered back to his brothers.
They were waiting for him near the old stone wall.
"Let's fool Sammy Red Squirrel first," said Billy.
"I saw him run out of his hole just a minute ago."