Yeats depicts nature and the natural world in "Sailing to Byzantium" as representative of the temporal condition of all living things. For Yeats, the natural world is a reflection of the reality which causes the speaker's struggle. The speaker understands that the world in which he lives is "no country for old men." It is one in which age is a part of the decaying condition. The first stanza speaks to how the natural world reflects a condition that all living creatures must face and experience:
The salmon‐falls, the mackerel‐crowded seas,
Fish, flesh, or fowl, commend all summer long
Whatever is begotten, born, and dies.
Yeats constructs nature and the natural world as part of the condition of decay, something that will make all creatures inevitably a "dying animal." There is nothing permanent in the natural world. Any force that is a part of this configuration must accept its own moral condition, one in which they will move to the realization that there is "no country for old men." The natural world is no different than any other condition of being in which over time creatures become "a tattered coat upon a stick." It is this understanding of nature and the natural world that the speaker encounters what he must embrace as his own mentality: "Once out of nature I shall never take/ My bodily form from any natural thing." The speaker is clear that nature and the natural world are bound by a temporality, a condition that haunts the speaker into yearning for something more. In this light, Yeats develops nature as a realm where age and mortality are conditions that have to be recognized and understood. Temporality can never be escaped, and understanding that "whatever is begotten" is born and killed is a necessary part of consciousness.