Bird song is an important influence on poets and poetry recurring across cultures and eras.
From A Poet’s Glossary
The following definition of the term bird song is reprinted from A Poet's Glossary by Edward Hirsch.
The vocal music of birds has always had a great hold on poets. “Sir, we are a nest of singing birds,” Samuel Johnson told James Boswell. The seventh century B.C.E. Greek poet Alcman of Sardis claimed to know the strains of all the birds. In Bright Wings (2012), Billy Collins points out that in early English poetry, “birds can be emblematic (the royal eagle), mythological (the reborn phoenix), or symbolic (the self-wounding pelican as Christ).” Over the centuries, poets have frequently identified with cuckoos (“Sumer is icumen in — / Lhude, sing cuccu!”) and mockingbirds, seagulls, herons, and owls. They have also noted their difference from us. They have watched them in their backyards (John Keats, “Ode to a Nightingale,” 1819; Anthony Hecht, “House Sparrows,” 1979), followed them into the woods (Robert Burns, “Address to the Woodlark,” 1795; Amy Clampitt, “A Whippoorwill in the Woods,” 1990), and tracked them to the shore (May Swenson, “One of the Strangest,” 1978; Galway Kinnell, “The Gray Heron,” 1980). They have treated birds as messengers from the beyond, the embodiment of a transcendent vocation. One thinks of Edgar Allan Poe’s raven, William Cullen Bryant’s waterfowl, Gerard Manley Hopkins’s windhover, W. B. Yeats’s wild swans at Coole, Robinson Jeffers’s hawks, Wallace Stevens’s blackbird, Osip Mandelstam’s goldfinch, Randall Jarrell’s mockingbird . . . The tradition of imitating bird song is so strong that it sometimes begs for counterstatement, as in Michael Collier’s poem “In Certain Situations I’m Very Much Against Birdsong” (2011).
The nightingale—a small, secretive, solitary songbird that goes on singing late into the night—has always had a special metaphorical and symbolic power. It fills an apparently irresistible need to attribute human feelings to the bird’s pure and persistent song. Poets, who are often nocturnal creatures, have identified with “spring’s messenger, the sweet-voiced nightingale,” as Sappho (late seventh century BCE) calls it. The romantic poets especially considered the bird a symbol of imaginative freedom. In “A Defence of Poetry” (1821), Percy Bysshe Shelley established the connection between the poet and the nightingale: “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.” The singing of the nightingale becomes a metaphor for writing poetry, and listening to that bird, that natural music, becomes a metaphor for reading it. One of the romantic premises of Shelley’s metaphor is that the poet “sings” in “solitude” without any consideration for an audience and that the audience, his “auditors,” responds to the work of an “unseen musician.”
The nightingale has had a rich history of representations in poetry, which begins with one of the oldest legends in the world, the poignant tale of Philomela, who had her tongue cut out and was changed into the nightingale, which laments in darkness, but nonetheless expresses its story in song. The tale reverberates through Greco-Roman literature. Ovid gave it a poignant rendering in Metamorphoses (8 C.E.), and it echoes down the centuries from William Shakespeare (Titus Andronicus, 1589) and Philip Sidney (“Philomela,” 1595) to Matthew Arnold (“Philomela,” 1853), T. S. Eliot (“The Waste Land,” 1922), and John Crowe Ransom (“Philomela,” 1923). Even without the mythological scrim, poets have often responded to the piercing woe-begotten quality of the nightingale’s song, which Keats beautifully imitates in his nightingale ode. Samuel Taylor Coleridge was the first romantic poet to attack the idea that the nightingale’s song was necessarily lonesome and sad (“The Nightingale,” 1798). In the 1830s, the rural poet John Clare observed how nightingales actually look, sound, and behave. “I have watched them often at their song,” he said. He objected to the old threadbare epithets such as “lovelorn nightingale” and with a naturalist’s eye remembered how assiduously he had observed one as a boy. Here is how he describes hearing a nightingale in his poem “The Progress of Rhyme” (1835):
“Chew-chew chew-chew” and higher still,
“Cheer-cheer cheer-cheer” more loud and shrill,
“Cheer-up cheer-up cheer-up” — and dropped
Low — “Tweet tweet jug jug jug” — and stopped
One moment just to drink the sound
Her music made, and then a round
Of stranger witching notes was heard
As if it was a stranger bird:
“Wew-wew wew-wew chur-chur chur-chur
“Woo-it woo-it” — and could this be her?
“Tee-rew tee-rew tee-rew tee-rew
Chew-rit chew-rit” — and ever new —
“Will-will will-will grig-grig grig-grig.”