The self-indulgent friars are

Like Jovinian,

Fat as a whale, and walken as a swan.

The Pardoner describes his own preaching in these words:

Then pain I me to stretche forth my neck

And east and west upon the people I beck,

As doth a dove, sitting on a barn.

Very often, too, Chaucer derives his happiest metaphors from birds and beasts. Of Troy in its misfortune and decline he says: Fortune

Gan pull away the feathers bright of Troy

From day to day.