The poem begins and ends with an omen. The first is one of hope: the rainbow, the other is more ominous: the birds, as in augury which, while she often uses birds as a sign of faith, here she mixes it with the the violent fates of Roman leaders – you can almost see the vultures circling overhead. She is also talking about how nature (feeling) communicates better than words / philosophy.
Her use of the word “gust” is interesting because she’s not just referring to a “storm” after which the rainbow will appear to signal God’s promise, but “gust” can also mean to express one’s enjoyment through speech. Yet what she is trying to say is that words and logic fall short of the signs of nature / God. Philosophy, of which Cato was a stoic and a lover of logic as the greatest virtue (think Spock from Star Trek), she is relating to just a bunch of spoken bluster. Chaucer compared speech to farts in The House of Fame when the professor / eagle says:
‘Soun is noght but air y-broken,
And every speche that is spoken,
Loud or privee, foul or fair,
In his substaunce is but air;
For as flaumbe is but lighted smoke,
Right so soun is air y-broke.
Furthermore, the Eagle in Chaucer’s poem is a representation of Rome, and this bird is a stuffy, boring professor who loves to hear himself talk but doesn’t manage to say very much. Emily is making a similar comparison to speech and worldly learning in that it’s all a bunch of blustery words, but even a bird can tell when a storm is coming without the need for a weather report and thus will fly away to a safer location. In this way she mixes the portent of augury in which she relates to Rome and Cato’s “eloquent” struggles with Caesar.
In the previous poem, “Sexton! My Master’s sleeping here“, the “Daisies point the way there”, yet in this poem the “flowers turn from Forums”. She is saying that the institutions of humanity are not infallible, and that faith in God (“rainbow”) is the only sign of truth and knowledge that can be trusted because even a “bird” knows how to read it.
There is a subtle irony here in that Emily can only express her ideas with words, the very things that can’t be trusted, and so the poem demonstrates the problem all humans run into in interpreting the world in that we’re always going to be imperfect and that our words, unlike God’s words , such as in John 1:1, “In the beginning was the Word, and the Word was with God, and the Word was God” which explains that the only true words / language is God’s, not humanity’s. Thus words will always fall short and fail to really say anything, which is why she uses “Cato” as her example because even as “eloquent” as he was, his fate was no better than Caesar’s or anyone else who has ever lived.
In other words, we live in a world of language and words, but this world we’ve constructed is false, no matter how well we speak, and eventually it will all end in our passing from this world with the possibility of a greater world beyond. In this way our world is the “storm” and the rainbow / omen is a sign that things will get better, but first we must navigate this treacherous world.