Birds sing love-songs from apple trees, From boughs soft-swinging in the breeze, And carelessly in joyous glee Trill freely to their brides to be; But birds are oh, so fetterless! They warble not in bitternesss, And never words from lips compressed, Can rob them of loves truest test — A heart-song sung within a nest.
Birds in apple trees sing to their future mates, swaying on soft branches in a light wind, and the poem treats this as the simplest kind of courtship: joyful, careless, and free. The speaker admires that freedom. Birds, she says, are "fetterless," unburdened by the things that tangle human love. They don't sing out of bitterness, and no clamped-shut lips or hurtful words can rob them of what she calls love's truest test, a heart-song sung within a nest.
The quiet contrast is with people. The poem never describes a troubled couple, but the mention of "words from lips compressed" hints at silence, coldness, or quarrels that can strain human affection. The speaker seems to long a little for the birds' ease, and the final line suggests real love shows itself in the shared home, not just in pretty songs. The mood is light and sunny on the surface, with a thread of wistfulness underneath.