Stemming the Aggressors

Damn harpies. We've beat that bunch into submission more times than I can remember... and they stay quiet for a time after each bout. This time, I'd thought that maybe it sunk in. Apparently not. Their memory may be a bit short, but if their numbers are thinned enough, they'll keep to themselves. Head into the valleys in the north and east and clear out a fair chunk of them for me, will ya?