How does the poet use symbolism in the poem, The Wild Swans at Coole?

The swans, which give the poem its title, symbolize the contrast between permanence and volatility. To the speaker, they illustrate how the landscape has remained the same for nearly two decades. Although the speaker has grown old and worn down, the swans remain as “brilliant” and “mysterious” as they always have been. They represent the fixed centre of a changing world.