John Burroughs, Birds and Poets, 1887

The very idea of a bird is a symbol and a suggestion to the poet. A bird seems to be at the top of the scale, so vehement and intense his life. . . . The beautiful vagabonds, endowed with every grace, masters of all climes, and knowing no bounds — how many human aspirations are realised in their free, holiday-lives — and how many suggestions to the poet in their flight and song!