I worked as an intern at the national aviary. it is definately an awesome place.
If you ask the keepers, they are more than willing to give you all sorts of juicy tidbits about the birds.
In the summer there is a free flight bird show, and year round there are daily opportunities to feed the birds and get a really close up look.
you can feed an inca tern, blue bellied roller, carmine bee eaters, lesser green broadbill, fire tufted barbett among SOOOO many more. I definately recommend visiting!