Not to quarrel with any of the good advice you've received, but I still remember a Joe MacDonald (spelling? With or without "a"?) workshop in which he made the point that long lenses were a mixed blessing and that it was usually better to get closer than to get a longer lens. This is somewhat cold comfort when my 700 is too short and there are obstacles that prevent a closer approach.
But there are non-photographic gadgets, especially portable blinds, that are supposed to help solve the problem of getting closer. They seem to work for hunters.
All kidding aside, there are books on wildlife photography. I have Joe's, haven't looked at it for quite a while or compared it with the competition so hesitate to recommend it or any other. But you'll learn more from a leisurely read than you will from semi-random comments on a bulletin board. Get a good book and read it.
Good luck, have fun,