This small bird, mentioned only once in line 11, carries significant weight. It symbolizes the speaker's emotional transformation. Rising "from sullen earth" at daybreak, the lark represents hope, joy, and renewal. Its upward flight mirrors the speaker's spirit lifting from despair towards happiness due to love.
Initially, "heaven" seems distant and unresponsive to the speaker's prayers (line 3). This symbolizes his feeling of isolation and lack of solace. However, with the introduction of love, the idea of "heaven" (line 12) shifts to represent a renewed sense of faith or hope.