“It is a Gremlin!” Patsy cried. “A big, black Gremlin!”
“No!” said Betty. “I’m sorry. It’s a black pigeon. I didn’t know you kept pigeons.”
“We don’t,” said Grandfather. “What’s more, he doesn’t belong on this island. He’s going straight on. Turn the horn about, Patsy—”
Patsy obeyed and once again Betty heard that steady flap flap of wings.
When the horn had been properly adjusted, she listened until the sound of the pigeon’s flight faded into nothing.
For a moment Grandfather Norton studied the pointing horn, then he said:
“That’s a homing carrier pigeon. The rookery he is seeking is somewhere near Granite Head. You may have made a very important discovery.”
“I—I don’t understand,” said Betty.
“That pigeon never came all this way from shore by himself. That’s not the way of pigeons.”
“Then you think he came from a boat?” Betty was beginning to understand.