"The Bird is the Feeling: Romantic Natural History and its Subjects" argues that Romantic natural history writers and the nonhuman objects of their work are mutually constitutive subjects. Unlike eighteenth and later nineteenth-century forms of natural history that consider the natural world as a set of discrete objects and species available for collection and cataloguing, the texts considered in this dissertation are primarily concerned with unexpected encounters and fleeting natural phenomena. The writers addressed express these unrepeatable encounters as a form of natural history that does the work of designating significant subjects and articulating their presence within distinct, subjectively constituted and construed environments. In reading the "natural history" journals, letters, and poems of Dorothy and William Wordsworth, John Clare, and Henry David Thoreau, this dissertation frames the Romantic turn to nature not as a turn away from sociality and history but towards alternative forms of both. Intervening in a number of established strands of Romantic literary criticism and ecocriticism that read the Romantic speaking subject's treatment of the natural world as primarily an instrument of ego-formation, "The Bird is the Feeling" celebrates the largely private, idiosyncratic efforts of Romantic authors to consider nature, history, and subjectivity in both human and nonhuman terms.