They show up in just about every zone. you just have to know where they spawn because typically in only two spots. In ravenfell, the spots are both at crossroads, the first where the main road branches to go to that one old mansion, the second where it branches to go to that air temple ruins place.
In Silverfall, the easiest by far. The first is at the bridge to where Yuri is, the second is a short distance along the riverbank as you head to Tagena, before you get to the second bridge, if you get to the second bridge you passed it.
In all cases, look for the sparklies.