@Great Argus Yes, that was it. The aviary is very tiny in terms of the little footpath that snakes its way through, but there is some height to the structure. Many visitors spend only 2-3 minutes inside.
@snowleopard Signage appears to be incomplete and quite possibly outdated was my reason of curiosity, I have some sources indicating several bird species at Oregon most likely in that aviary. Some of them were present years ago when I visited. The gallinule has been signed for many years, I don't believe any Zoochatter has spotted it to date though.
