Olm the Wise is a level 48 non-aggressive rare owl (bird of prey) that can be found in the northern part of Felwood. I have indicated where he can be found and where I found him in red on the map below. He is especially desirable as a hunter pet as he has a unique transparent skin. He looks like he could be a spirit beast, but isn't. He is tamable by all hunters in any spec, and is a cunning pet.
Olm the Wise seems to have at least a couple of spawn points, I found him in the northern one.
Olm the Wise can be found with NPCScan. You will need to add it, his NPCScan ID is 14343.
You can also use this macro to help find and tame this guy:
/tar Olm the Wise
/cast Tame Beast
Olm the Wise seems to be on roughly a 7-8 hour spawn timer.
Once tamed, he has a couple of special abilities. They are Snatch which grabs the enemy's weapons, disarming them for 10 seconds and Play which may or may not work on him (in the tool-tip it says "Larger Birds may not be Interested")... In the video below I tried to get him to play like three times but he didn't seem interested, I guess he's a big bird.