Your master's program may offer you a nonthesis option. Usually this means that you take a comprehensive exam to demonstrate your knowledge of the subject. The thesis option makes more sense if you intend to continue to the doctorate. Researching and writing a master's thesis helps you acquire skills you need in the doctoral program.
There are about 50 separate wildlife biology programs. This subject may also be studied within a forestry department. If so, you may also study principles of forest growth and maintenance.
Some master's programs include an internship. You do supervised work in a setting that involves an aspect of biology, such as a wildlife management agency, an aquarium, or a research lab.