nice shots Buddah Jones. Great exposure and color. Shooting thru glass is always tricky. Have done it at St. Louis zoo. They allow flash. Some tips.
1. Try to get flash off camera with cord. Really cuts down on reflections.
2. Do use a big rubber hood against glass if possible.
3. Macro lenses work well as do wide angles. Love using the 10-17 FE.
Years ago a few of us went to the zoo to shoot. We were doing indoor flash of fish and reptiles. None of the critters seemed to mind the flash. There is this important looking display with an endangered Gecko in it. Friend fires up the Pentax LX and strobe. The darn lizard jumped straight up in the air about a foot! Scared the heck out of us. Thought we had killed the thing. It was fine but we left quickly.
No other reptile reacted to flash that day.
thanks
barondla