Spenser describes nature in great detail, loving reporting on the weather, naming flowers, and interpreting the currents of the Thames. As he does so, he often gives these inanimate objects human characteristics, making it seem like they have desires, fears, and the capacity to act. For instance, in stanza 3, he personifies the river by suggesting it is afraid to get the swans' feathers dirty:
[...] even the gentle stream, the which them bare,
Seemed foul to them, and bade his billows spare
To wet their silken feathers, lest they might
Soil their fair plumes with water not so fair,
And mar their beauties bright,
That shone as heaven's light,
In this passage, the river is sophisticated, perceptive, and respectful. The swans fear that the water will make their feathers dirty; the river seems to perceive their fear and responds to it, controlling his body, keeping his water from touching their feathers. The river is not simply an inanimate object on which the swans float. He is, instead, an active participant in the drama of the poem—its glorification of the swans and their upcoming wedding.
This alerts the reader to a general pattern in the "Prothalamion." When nature is personified in this poem, it usually acts to reinforce the rituals—and the hierarchies—of human life. For example, in stanza 7, the birds that live along the Thames "enrange" themselves around the swans as they travel down river. The word "enrange" suggests that the birds not only follow the swans, they also arrange themselves in a hierarchy around them, offering "their best service." (The speaker does not tell us what the basis of this hierarchy might be: whether some birds are more beautiful than others or somehow more noble, or whether some other criteria is in play). The birds are granted the capacity to perceive social difference; with that capacity, they recreate, spontaneously, the hierarchical, highly stratified structure of Spenser's own society. In this instance, personification reinforces the structure of human society: suggesting that structure is itself natural and inevitable.