I was in Florida this past week and got to borrow a 300mm f/4 IS lens to shoot some wildlife. It's a pretty challenging lens to use since you only have foot-zoom. I don't know how people managed to catch birds in the old days with film, manual focus, and no IS =b
Nice pics. I especially like number one just for the feel of the pic and the colors. Number two is cool for the depth of field effect. Then I like number 4 for the lines (that's not really what I am getting at, but resolution? detail? basically, how you can see the feather's really well).