The fact that Raven's, like any other creature, will get tired and will want to stop to have a rest.
Look how well this crow does in the water.
So, I think it's fairly obvious that if a raven (closely related to crows) wants to stop flying and rest, it is not going to just settle down in the water like a duck or gull would. Because it would drown.
Yes, birds can navigate with magnetic fields, but a compass isn't really going to help if the entire world is covered in water and the only place to rest without drowning is a moving boat.
If I dropped you in the ocean with a compass and told you to find a nearby ocean liner, could you do it?
No, this is not evidence of God.
It is evidence that a raven will get tired after it has been flying for a long time, and it will want to rest. And as we saw from that video, a raven needs a solid surface to rest on. If the only thing it can find is a boat, it will go there. It does not need a homing instinct to do so. It requires only the "I'm tired and about to fall out of the sky" instinct as well as the "I don't want to drown" instinct.