Our first clue that the Yeats poem may be related to the earlier Keats poem occurs in the first stanza, when the speaker calls the birds singing in the trees "dying generations," a phrase quite similar to one in Keats's ode--"Thou wast not born for death, immortal Bird! / No hungry generations tread thee down." From that moment on, the poems are as thematically opposite as is possible for two poems glorifying art. Keats's nightingale (a natural bird) is a symbol of lyric fluidity, expressiveness, change, and union with nature; around the nightingale, Keats thinks that it would be "sweet to die" and "to cease upon the midnight with no pain." Yeats's golden bird (an artificial bird) is a symbol of permanence, knowledge, unchangeability, and a liberating separation from nature; Yeats longs to be "gathered into the artifice of eternity" precisely because he does not wish to age and to die.