Personification is when an object, abstract concept, animal, event, or idea is given human characteristics or senses. A common example of personification is when a boat is referred to as "she." In this case, the boat, an object, is personified.
Personification is used in Percy Bysshe Shelley's poem "Ode to the West Wind." He addresses the West Wind as "Thou" in the second and fifth lines. The use of personal pronouns to describe an event, animal, object, or idea suggests the poet is using personification. The speaker of the poem calls the Spring wind the (Autumnal) West Wind's "sister" indicating the two seasonal winds are siblings.
In the final couplet of Part 1, the speaker personifies the West Wind with supernatural abilities:
Wild Spirit, which art moving everywhere;
Destroyer and Preserver; hear, O hear!
Even though this sounds like a comparison of the West Wind to a god, it is still a personification.
In Part 3, the speaker personifies the Mediterranean Sea. This is indicated by the pronouns "he" and "his" which refer to the Mediterranean.
Often, poets will use human senses or body parts to express a personified object or concept. In William Blake's "To Spring," the speaker describes Spring looking down upon the "western isle." In turn, the western isle is also personified as it is "in full choir" and sings to welcome Spring, "hails thy approach." In the second stanza, the hills talk to each other. Spring is also given human features such as having "angel eyes," "feet," and "breath."