So as far as I understood it, it's a smallish owl, and definitely not at the top of the food chain. So when it encounters a possible threat that's only slightly larger than itself, it puffs up to look bigger and more menacing. But when it encounters something much bigger than itself, it shrivels up and pretends it's a branch. "Nobody in here but us tree stumps. Not edible at all."
And I love the way it keeps the thinner (and bark-coloured) side towards the predator. If you want to appear slimmer on photos, just do what the owl does