Comments by Date (2)
These pets do seem to have a bit of a long spawn timer. Keep checking back and you will find them.
The strategy that worked for me was to park a lvl 45 alt there, and when checking, ride around covering all the Dry Hills area, including the entrance by the prowlers/lions, and entrance on the opposite side...basically everywhere you see an adult harpy.
In some ways I think being on a ground mount is better in this case, because you don't have to go through all the trees, land, target, fight. Create a macro to target the youngling, and bind a key to interact. That should help a lot.
I have seen more outside of Everlook than in it. I would recommend starting in the center of Everlook, go outside to just across the road, then make a big circle around the town. That should cover all the area that they can be spotted in. The coordinates below are a good guide as well.
They typically seem to spawn in places where the Rabid Varmints, Rabbots, or Robo-Chicks spawn. I'm not sure there is a correlation between killing them and cubs spawning...but it kills some of your waiting time.