My guess would be that these are in the "Wyvern" family since in their PoL description they are called "Wind Wyverns."
While heading through Wajaom Woodlands going to get a staging point we ran into these. At the time people had assumed them as True Sight when really they are Sight AND Sound aggro. Meaning you must have both Sneak and Invisible on around them.
As mentioned by SE they are "Wind Wyverns" and using any sort of Wind based element/ws/weapon/etc on them will heal them. This little bit of info was pulled of BG Forums.
I actually got aggro from one on my DRG and they have a nasty knock back AoE. It nearly knocked me clear back into a mob of Puk so I had to position myself with my back against a ridge. I can't recall if I intimidated it at all as I was more worried about dieing than intimidating it. Conned DC I believe to 75.
I thought they might either be lizards or vermin, but I have yet to see them be intimidated, or cause intimidation, for either beast or plant type mobs. Maybe these things really are charmable wyverns. I don't know of any demons in the same area as them to check this with. Maybe they'll make a jug pet for these things eventually.
Along with their wind knockback move, I've also seen them use Zephyr Mantle, which is basically Utsusemi: Ni, and Obfuscation, which is Flash.