For anyone who looked at the pictures and still wasn't sure what the bird was, there is general agreement that it is a juvenile Herring Gull.
I never like looking as if I don't know things, but I figure I have two choices. 1) Don't ask, and people won't realize that I don't know things. The drawback is that I would continue to not know anything. Or, 2) Ask, let people know that I don't know, and then learn. Option 2 always seems better. We have such a vast collection of great resources (people) here in Colorado that it seems silly not to take advantage of it. It's like having our own personal Ornithopedia (if you don't mind that I butcher the Latin language a bit).
Thanks to everyone that took the time to look at the pictures, and extra thanks to everyone who took extra time to respond. I appreciate it.
John Breitsch
Denver, Colorado