Before humans could notice their tail signs of what was to come, animals where the first creatures to notice it all, that is why you have to pay close attention to the way that they act and how they respond to different movements, look at how we tell the weather, we get our information from a ground hog, whether he sees his shadow or not.
I think that animals do sense things and although it could just be a random thing going on,it would not be surprised if they are sensing change and athat there would be a volcano eruption happening. Animals could be trying to protect themselves from what is ahead and could feel the change in the ground.
A supervolcano eruption would destroy the earth as we know it. The sun would be clouded out by ash, and the world would not function. Supervolcanos do not operate like regular volcanoes, and are vastly unpredictable. However, there is not a strong claim in saying that bison migrating has any correlation with an eruption. While animals can sense natural events, this is a stretch at best.
I hope the bisons seen fleeing Yellowstone national park is not a sign that the super volcano there is about to erupt. There are several other factors which could have caused this, such as tremors underground or approaching vehicles or people. For everyone's sake, I hope it's not the super volcano there.