I feel such grief o’er a bird with a broken wing; I feel so sad that the little thing Has been clipped of its passage through the air; Bereft of its feathers, its songs of cheer — Sitting in solitude.
A small injured bird is all the speaker sees here, and it's enough to stir real sorrow. The opening line states the feeling outright: "I feel such grief." The next line repeats it with "so sad," as if the speaker can't quite get past the emotion and keeps circling back to it. There's no argument or lesson being built, just a heartfelt reaction.
What the speaker mourns is a double loss. The bird can no longer fly ("clipped of its passage through the air"), and it has lost its songs of cheer too. Flight and song are what make a bird a bird, so the injury feels like the removal of its whole identity. The final line, "Sitting in solitude," is short and still, and it leaves the bird alone in the quiet where music used to be.
The mood is tender and melancholy, gentle rather than dramatic. The speaker's compassion is the center of the poem.