Howling Stones Combinations and Locations
In Zelda the Twilight Princess there are 7 unique skills for you to learn through an ancient warrior that you meet in the game after you find a Golden Wolf. You get one of these skills by normally progressing through the game, Finishing Blow. That leaves 6 left for you to find by yourself.
None of these skills are required in order to beat the game but each of them will give Link (you) a signifigant advantage in defeating certain types of enemies within the game.
You can only activate the Howling Stones within the game while you are in Wolf form. You can get a majority of the Howling Stones the first time you pass through the area while it's still in Twilight but for the purposes of this guide I am going to assume you didn't.
It's easiest to collect the Howling Stones (in my opinion) once you've acquired the Shadow Crystal midway through the game. This allows you to transform to and from a wolf at your leisure making Warping around the world and doing tasks such as this much easier and drastically less time consuming.
When you activate one of the Howling Stones it will place a marker on your map, like the one shown in the screen shot below. You'll have to go to this location as a human and interact with the Golden wolf that is at this location. Doing so will begin the cutscene for granting you that skill.
This guide will list each of the 6 locations that you can find the Howling Stones and it'll give you the combination for the Stone itself. Knowing what to howl can be a bit of a pain, I would assume even moreso if you don't have a musical bone in your body.
The rest is up to you, it should be easy enough since they literally mark your map!
This is the first Howling Stone you're able to retrieve on your own. It's also the one you'll have to wait the longest to get if you miss it. While you travel through Death Mountain for the first time as a Wolf you're able to activate this Howling Stone - it's found in the central area of Death Mountain that's littered with geysers.
The Howling Stone in northern Faron Woods can be found just outside of the entrance to the Sacred Grove. You'll pass right by this your first time through sacred grove as a wolf. Alternatively once you obtain the Shadow Crystal in the Sacred Grove you can come back to this stone any time by following the same path you took the first time here.
You can get this stone your first time through Zora's River while the region is still covered in Twilight. If you missed it your first time through you'll have to wait until you get the Shadow Crystal later in the game which lets you freely transform to and from a wolf. The Howling Stone itself is extremely easy to find, it's on a hilltop overlooking the river rapids ride building.
This Howling Stone won't be able to be reached until you have the Shadow Crystal about midway through the game. It's found atop a ledge in southern Lake Hylia that you must climb a ladder to reach.
The Snowpeaks Howling Stone is found near the top of the mountain on the side of Snowpeak closest to Zora's Domain. You won't be able to get this Howling Stone your first time through Snowpeak since you can't stray very far from the footprints you have to follow. You'll have to fast travel back later to acquire it.
The last Howling Stone in the game is found within Hidden Village of Eldin Province. You can't reach this location until much later in the game after you've acquired the Dominion Rod. In addition, the song combination for this Howling Stone is one of the most difficult ones you've had yet.