A thought on Shelley’s birds

Among the striking sentences in Shelley’s A Defence of Poetry is the following:” A Poet is a nightingale, who sits in darkness and sings to cheer its own solitude with sweet sounds: his auditors are as men entranced by the melody of an unseen musician, who feel that they are moved and softened, yet know not whence or why”(861).   Several things are working in this sentence that also function in To a Sky-Lark.