Power
As a (Fish and) Game Warden, you are a public servant. One of the benefits of this arrangement is that government agencies often stick with the people they know. Coupled with certain federal, state, and local regulations regarding employment, promotion is almost certain for the career conservation officer. There are hundreds of county offices and wildlife refuges around the country, and each one of them needs someone in charge.
This rise in office is accompanied by a rise in responsibility, and that means more power. You'll have a staff of troopers to whom you can dictate commands (in a nice way, please). You'll soon be choosing whom to fine, which persons or companies to investigate, which schools will have access to the parks on which day, and even whether to get the new uniforms in beige or chartreuse.
Eventually, you could be in charge of an entire state's forests, lakes, and rivers. Could you imagine being responsible for the enforcement of wildlife laws in a state like, say, Texas? When you're running the entire Texas Parks and Wildlife Department, you're overseeing all operations conducted by hundreds of public employees. At that point, your power is hotter'n a goat's butt in a pepper patch. For those who don't speak Texan, that means that's some serious power right there, I tell you what.