I heard Loren Coleman say in an interview that in the early part of the Mothman episode, what was being discussed was an unusually large owl. The witnesses didn't know what they saw, but I think even some of them thought it might be a "gigantic" owl. The headless winged humanoid creature came along later. I was surprised to hear him say that, given some of the other things he's said and posted about it. There was plenty of weirdness in Point Pleasant without "Mothman", and you don't need any of John Keel's experiences either to have a very strange episode.
Interesting that the descriptions are so similar, a couple of thousand miles and several decades apart.