The American Trail had been closed for renovation on my first trip to the National Zoo, but had reopened by my second trip there.
Here's a beaver. Unlike many other beaver exhibits I've seen at zoos, I didn't see a viewing window into their lodge, probably because it was mostly built by the beavers themselves.
A pair of hooded mergansers live alongside the beavers.
A North American river otter asleep in its den.
A brown pelican and (the hindquarters of) a California sea lion. Brown pelicans are one of the few pelicans that fish by diving from the air, but the ones at the zoo have permanent wing injuries that prevent them from flying.
Other animals I saw but didn't photograph were gray wolves and gray seals, and ones that were present at the zoo but I didn't see included ravens and bald eagles. Don't worry though, those ravens and eagles will get their chance to shine yet.