The correct answer to this open question is the following.
Although there are no options attached we can say the following.
The owl is one great example of how mother nature helps its creature to evolve and adapt to different circumstances. The owl has mutated over the years and genetic modifications have allowed it to become a silent hunter at night.
What happens with the owl's wings is that the owl is capable to alter the turbulence or the wind and reduce the noise produced by the air. The serrated form of its wings has small fringes that according to zoologist, allows the owl to reduce the noise produced by the air. That is why when the owl flies, it is practically undetected by the prey.