This eagle is funny because he’s basically an idiot Virgil. Unlike in Dante’s Divine Comedy when Virgil was a helpful guide for the poet, this eagle is more of a know-it-all that Chaucer finally has to say that he’s just no longer interested in learning anything new from him.
There is more to the joke, however. As the eagle explains how the House of Fame receives its news via broken air – speech and noise break the air and that travels up to the realm of the House of Fame – then speech and sound are not really differentiated. In fact what a person says vs. them farting would be of equal importance, thus speech is basically a fart.
And while this is typical Chaucer humor, it’s deeper than it seems because he’s also alluding to the possibility that prayer, at least as it is intoned, is also about as valuable as a fart. Private prayer, silent prayer – thus (hopefully) earnest prayer – is usually thought, but public proclamations of virtue and showy prayers hold the same importance as flatulence: shitty air / shitty wind.
Another observation is who is this god of love Chaucer is referring to? Does he mean Venus? Well, no because here the god is masculine. Does he mean Cupid? Or does he actually mean Jesus. God is, after all Love thus in the 13th century evoking Jesus would give the poet the moral authority he wants to write imaginatively about love.