Very nice images! I was at the National Zoo today with a 70-200 & a 1.7 tele-extender. Couldn't get that close to most of the animals, but had a few that worked out.
A bit disappointed with the National Zoo. I was really looking forward to seeing the eagle, but those birds are not on display not due to some construction.
Saw the pandas. At first, I was disappointed because they were only indoors - behind glass in a concrete setting. Got lucky, though. I was about to leave the park when I heard some animal scream a couple of times. Turns out it was the panda. Two of them came out, each with a milk crate. They liked the snot out of those milk crates, put them on their heads to lick the inside, etc. I don't know what it was about those crates, but they loved licking them.
The lions had a bit of play, but mostly were just hanging out. One of the gorillas jumped up and slammed the glass at some little girl, but I missed the shot.
Overall, it gave me more of an appreciation for Animal Kingdom.