If you're going to take courses, I'd suggest you take them in zoology, wildlife preservation and management, or related fields about wildlife. While learning to master your camera and getting the correct lenses and support gear and learning the proper techniques for the type of wildlife you want to shoot is going to be important, the one skill you absolutely must master to shoot wildlife well is fieldcraft.

If you can't get to where you can see the beasties, you're not gonna be able to take pictures of the beasties.

Wildlife photography isn't just about snapping shots, it's also about learning how to stay downwind, how to use a hide or ghillie suit, how not to stress out an animal, knowing the right locations and seasons to find them, what they feed off, and what their natural behaviors are. At its best, it's about knowing about the animals as individuals and families. About knowing their biology, their anatomy, their breeding habits, the destruction/preservation of their habitats, migratory patterns, etc. etc. etc.

The quality of an image typically is about the time, effort, talent, and sheer determination the photographer put into getting the image. Go watch a behind-the-scenes episode of any of the more recent HD BBC wildlife series, such as Planet Earth and realize that each of those short segments probably took anywhere from six months to a year to plan and execute. That living in a hide for three weeks in an Amazonian jungle is how that National Geographic photo gets taken. That if you want to shoot snow leopards in the wild, you have to learn how to climb the Himalayas.

You can practice with a cheap 70-300 on the backyard birdies. This is the fun of learning and beginning. But I think this type of subject is more a matter of getting out there and doing it than sitting in a classroom learning about how to use back-button autofocus and supertelephoto holds. You can get that stuff off the interwebz. What you kinda can't get that way is terrific knowledge of who's in your own neighborhood.