Answer:
On Page 2, we learn that travelers came long distances to observe the "abundance and variety" of bird life. Other came to fish.
So the the answer is birds and fish.
In "Tell Tale Heart" by Edgar Allan Poe, the beating heart the narrator heard symbolizes, at least in my opinion, the narrator's guilt.
He killed a man, and he kept hearing his beating heart, even though it was impossible. He kept hearing it because he felt guilty because he murdered a person, and he had to come clean to the police officers in some way. If he hadn't, he would go completely mad, and his crime would go unpunished, probably.
