I had a lot of previous experience with helicopters while working in the wildfire biz. After that I ended up working for the state department primarily doing survey work along the western US/Canada border. In Alaska and a lot of the mountainous parts of the NW, getting to survey sites along the border would be impractical/impossible without a helicopter. We contracted work with quite a few different helicopter companies, but in Alaska we always used the company that I ended up working for doing the wildlife capture work. Other than a couple of Canadian pilots we had worked with, those capture pilots were on a whole different level. I got to be friends with one of those pilots. He really had no choice in the matter since we were mostly working out of tent or remote work shack camps and were stuck with each other for months on end. He showed me some of his capture videos and I talked him into talking the owner of the company into giving me a shot.
I don't think you will ever see a job posting for a mugger or gunner position. Its a pretty tough nut to crack and you pretty much have to be recommended by someone in the industry. It is also definitely not for everyone. Over the years that I was part of it, I got to work with quite a few guys that thought they were pretty tough. Not many of them made it a week. Not to say I'm particularly tough...more of a combination of hard headedness and a lack of self preservation.