How does williams set up a contrast between birth and death in "landscape
with the fall of icarus"?

By telling the reader that "it was spring".

Explanation:

William Carlos William's poem "Landscape With the Fall of Icarus" is in relation with the painting of the with the same title by Pieter Bruegel. It talks of the fall of Icarus from the sky and the moment of his fall into the water.

Opening the poem with the lines "When Icarus fell, it was spring", Williams presented a stark contrasted picture. This contrasted picture also point to the image of the two stages of life and death, birth and death being the two sides of humanity. Spring represents the abundance, the start and colorful beginning while the fall represents a fall from life, a metaphor of death. Thus, the poem, short as it may seem, is a representation of the contrasting nature of living and dying, birth and death.

the roman empire began to fall