I was using a 34 druid to quad Dire Wolves to the south/east of the druid portal. After about 2 hours of this I noticed A Dire Wolf Stalker up on track.
He was further south/west of where I was and found him easily along the coastline wandering.
He is quite fast and i was afraid I would have trouble getting ensnare to stick as he was yellow to me. I memmed snare as well and kept hitting him with that till it stuck. He is almost as fast as SoW but not quite. After I got snare to stick then I overwrote it with Ensnare since I could outrun him easier now. I kept dotting him with Drones of Doom over and over as it wore off and would meditate in between since I didnt have the mana needed to blast him to death.
I did use Careless Lightning somewhat for full effect almost everytime. I couldnt get fear to stick on him though.
He dropped the map piece and I believe he drops it everytime.