For as large as they are, and the weight of their prey that they can carry, owls are surprisingly light.
I was privileged to have one sit on my hand (heavy leather gloves) at a recovery center. This one allowed you to touch it's back and feathers and they have a good inch of fluff over their bodies, too. Not at all like the domestic chickens and turkeys that farmers raise.
I'd not worry about the wind vane. And indeed they are silent flyers.