Grandfather Frog in "Billy Mink Finds Little Joe Otter"

"It's a splendid chance to have some fun with Grandfather Frog and give him a great scare," concluded Billy. Little Joe Otter put his fish down and grinned. He likes to play pranks almost as well as he likes to go fishing.
"What can we do?" said he.
"I've thought of a plan," replied Billy. "Do you happen to know where we can find Longlegs the Blue Heron?"
"Yes," said Little Joe. "I saw him fishing not five minutes ago."