Audino can be found in all these areas:
Routes 1, 2, 3, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 18, Dreamyard, Dragonspiral Tower, Abundant Shrine, Cold Storage, Giant Chasm, Lostlorn Forest, Village Bridge, Pinwheel Forest.
They can only be found in shaking/bubbling spots though. They are the most common things in the shaking/bubbling spots.
Every time you take a step, there is a small percent chance that an on-screen patch of grass will start shaking. Knowing this, if you run back and forth next to some tall grass, it won't be long before a patch of rustling grass containing a rare Pokémon will appear.Rustling grass is found in Generation V, in virtually any area with patches of tall grass. Occasionally a patch of grass can be seen shaking. Entering such a patch triggers a battle with a wild Pokémon. The Pokémon found in rustling grass differ from route to route, but all areas contain Audino. In most areas, it is possible to encounter in rustling grass the evolved forms of Pokémon found in regular grass. If the player hovers around the grass for a fixed amount of time without entering it, it is possible to create a rustling grass spot at a random grass spot. Dark grass does not rustle.