Owls, being night creatures, are thought to survive various challenges including whatever may happen or whatever creatures exist in the dark. They can see very well in the dark and since they fly, they should be able to escape danger easily. So when an owl is found dead then there is no way that can only be explained as an act caused by the wind. There must be something tangible that must have led to the owl’s demise. Our elders used these same circumstances to explain that there are no incidents without a cause. Some things need to have plausible explanations.
The proverb is used to dismiss a feeble and implausible explanation to an occurrence and particularly when the explanation seems made up to conceal the true cause. The proverb supports the law of causation that there can be no smoke without fire.