a lesson in feathers

We found a sawhet owl, that had collided with a vehicle, dead by the side of the road. So of course we took it home for further investigation.
All nocturnal owls are known for silent flight, so that they can sneak up on their prey. How does that work? They have "fimbriate" leading edges on their primary feathers, that is, thickened, comb-like, ends on each filament to muffle any wind turbulence. 
This is a close up of the first and second primary feathers of the right wing, with the leading edge on the right. Can you see the knobby ends?