Really well done. I can't believe you saw the beaver swimming in the daytime. I don't think I have ever seen that. They are always sleeping in their den and the only time I have seen them out at the pond is during night openings.
I have one minor correction. You state it is located in Saguaro National Park. It is actually located in Tucson Mountain Park, a county owned natural area that is adjacent to Saguaro National Park. The two parks join seamlessly to form one large natural area, so it's easy to confuse the two.
