I've seen small birds drive away an owl before, and I think that's what is happening here between a songbird & a Barn Owl. It's astonishing to witness the bravery of small creatures protecting their young and/or their territory.
How is that this owl is living in the snow? The owl has adopted to its environment. Nature found a way to make it work. We tend to find ways to go against nature. Let's get back to being one with nature.