I think this bird was a tourist visiting the attractions rather than one of the guests -- it's not uncommon to see herons locally. It was wading in the hippo pool, near the okapi pen.
Taken Monday, May 28, 2001, 12:57:42pm. Original image size: 1600x1200, 1061kb
Technical details: Olympus C700UZ, 1/200s @ F3.5, ISO 100, 266mm