Amphibians in Colorado

A tadpole, found on 9 August 2008 in a pond at the Fountain Creek Nature Center. It is very small, so must be young. Species unknown, but there are some Bullfrogs in those ponds.
Bullfrogs, found at the Fountain Creek Nature Center on 7 September 2008 (first two pictures). It is difficult to get close to these for photos, since they are very sensitive to vibrations in the ground, so they know I am coming long before I can get close enough to see them.

The third bullfrog was at the same place, but on 5 May 2009. I was able to get fairly close with out making him/her nervous.

Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Anura
Family: Ranidae
Genus: Rana
Species: R. catesbeiana