Thanks for all the comments. I took this shot with a Nikon 28-70mm AF-S at the 70mm end. I was lucky that the pelican was pretty accustomed to humans and let me get pretty close before he took off. He was maybe 15 feet away. The shot is cropped a little. The Sigma 50-500mm lens (Bigma) is nice, but the Nikon is better -- you just have to be a whole lot closer.