Thanks for your detailed response. You're right, moving around is limited with large accessories or lens. I have an idea of moving with the tripods is often more difficult. I bought a Canon 700d second hand one year before coming to Canada. (280 euro with less 300 shoots). When I was in Algonquin Park last winter I saw a photographer with a 420mm lens. At the moment I am planning to keep make practice with my Canon 700d. In the near future, I am planning another lens. I do not know Nikon very much but with Canon almost all accessories are compatible, the main reason I found and I chose that camera, plus the cost I mentioned before. That's why your job was great is not easy to capture such an animal when is going to move and/or specific moment of it :) :)