The Frog is a confident, arrogant creature who doesn't care what the other animals think of his singing voice. He just wants to be heard above everybody else. He tells the Nightingale that he owns the sumac tree, but the reader gets the impression he doesn't own it at all. He just wants to make himself sound and look more powerful than he is. The poem suggests that his one aim in life is to "display his heart's elation." The problem is that, in the context of this poem, he has a hard, dark heart.

In comparison, the Nightingale is an unassuming, impressionable, naive creature who sings entirely for the love of it. When the animals applaud her the first time she sings, she is surprised her voice could have such an positive effect. After the Frog starts coaching her and selling performances of her singing, however, she becomes "addicted to applause quite unrestricted." By the end she has lost her love of singing and is a pale imitation of her former self. She has put far too much trust in someone she didn't know, and without ever questioning his motives.

The Nightingale was unsure, gullible, and naïve. On the other hand, the Frog was cunning, ruthless, and malicious. The frog sang horribly to the chagrin of the other animals in the forest. The other animals tried to stop him, but their attempts were futile.

The Nightingale arrived in the forest and sang melodiously to the pleasure of the animals. The animals loved how the nightingale sang and applauded her. The frog was jealous and hatched a plan to destroy the bird. The frog pretended to be an expert singer and an adept critic. He offered to help improve the nightingale’s singing. The nightingale unquestioningly agreed to follow the instructions of the frog. She failed to consider that her singing was impressive. She blindly accepted the frog’s claims of being an expert. The frog took advantage of the nightingale’s naivety and forced her to sing nonstop. The malicious exercise led to her demise.