Gray Tree Frog, near Waterloo, IowaThis is probably the most common North American tree frog. It can come in many colors depending on location — like chameleons, they have the ability to change depending on their environment (although not quite as spectacularly). As the name implies, they can appear anywhere on the gray to green spectrum. They are predominately found in southern Canada and the US states east of the Mississippi, although I spotted this one just west near the town of Waterloo, Iowa.
Nikon D700 with Nikkor 70-200mm lens (at 200mm) with Canon 500D close up filter, ISO 160, f/16 at 1/60th of a second, two Nikon SB-800 flash units