The speaker is riding past when he spots a tiny owl, no bigger than a sparrow, perched on a branch. What strikes him is not its size but its absolute self-possession: it has no doubt that it is an owl, and no interest in being anything else. That unthinking assurance stays with him. He starts to reflect on what it means to be fully yourself without fretting over it, but then he stops short. He says he won’t philosophize, because too much gets made of that idea — a small truth gets inflated into grand talk, and words can turn into bluff. The mood is wry and deflating, but also quietly admiring. The owl becomes an image of confidence that doesn’t need to think about itself: it simply is what it is, and the poem respects that by not overexplaining it.
Mister Owl — Summary
A little perfect owl, size of a sparrow But an owl by manner of intention I discerned in a flash on a wee branch As a seat in a vehicle bore me by. It had no doubts about being an owl I repeat, quite certain and casual.
To be what you are with no intention Or concept of being otherwise, With only the dimmest thoughts about that Is something of which I won't philosophize; There being too much made about that stuff: So much hyperbole about small truth: Lies shielded by poor refugees from bluff.