Mystical Visions and Concern for Human (and Animal) Life
Because of the mystical spin, you know this is a Blake poem. Sure, there are other poets who get pretty spiritual—Walt Whitman being a closely related example—but few claim to have actual visions and be directly in touch with Eternity. That's probably the thing Blake is best known for, really—people think of him as being either insane or an enlightened seer. (There's likely enough fodder in "Auguries" for both sides of that debate.)
Here's an example: "The Bleat, the Bark, Bellow, and Roar / Are Waves that Beat on Heaven's Shore." This is implying that the forces at play in the material world—symbolized by animal noises—actually reach out to affect and touch the world of eternity, or heaven. (Yeah, we told you folks thought he was kooky.)
Also, animals pop-up all the time in Blake's poetry: "The Tyger" and "The Lamb" are classic examples. He's a poet who is unusually sympathetic to the animal and natural worlds (even though he also said that Nature was just a grand illusion). Frequently, he uses animals as a way to say something about humans—indirectly, so you can see it in a new way. For instance, in "Auguries of Innocence" he says, "The poison of the honey bee / Is the artist's jealousy" (49-50).
Blake's always concerned with human suffering—and animal suffering as well. His poems are rich with compassion, and constantly chastise humans for not being kinder to each other. Blake really didn't like bullies or anyone who was causing suffering to anyone else, but his method is (usually) not to totally damn them, but to hold up a mirror. He's trying to give the Great Britain of his time the chance to get a good look at itself and its flaws, in order to help it to change. "Auguries" does this constantly. It's classic Blake and one of his most characteristic calling cards.