You can hunt small game with Phillips head screwdrivers, its not necessarily the knife but more on your technique and skill level. It would be pretty inhumane to just buy a set of throwing knives and trott off into the woods beaning squirrels and such with the handle of a knife! Here's your sign!
Master the art of throwing for a year or so and then you will know when you are ready to take any game. All the best.