yeslittlehummingbird

I love Hummingbirds... I never even thought this could be a potential job possibility. This is so cool to me. So with that in mind: How does one go about becoming a biologist / ornithologist who specializes in Hummingbirds? What are the prerequisites and requirements for such a field? Where do you even work?!

I noticed the aggressive bit when I got to watch them daily! Is there any really specific reason they're so aggressive? Why so aggressive for such a small birb? (I assume it's territory based, but I'm intrigued!)