Hmmm. I’m no expert, but my brief experience with NA oral tradition is that it doesn’t make fine distinctions between the species. It’s not “the gray wolf said to the brown wolf”; it’s just “wolf”.

The article does point out tribe-specific differences in animalism associations; perhaps those differences derive from which owls were most common in those local regions, and their behaviors? But if the legends themselves don’t distinguish which owl species is represented in the story, all we could do is speculate.