I have a little bit of historical information about the zoo via the release of the informative memoir Keeping the Zoo: Memories of a Forty-Four-Year Zoo and Aquarium Career (Houck, 2025).
John Horton Houck spent the first dozen years of his zoological career at Oregon Zoo, from 1974-1986, before moving on to Point Defiance Zoo for decades. The first third of his brand-new book focuses quite a bit on Oregon Zoo and I learned some things from reading his enlightening prose and there's a lot of wonderful stories. However, as a zoo nerd it's fascinating to find out that the Primate House, which was built in 1959, had a closed-down wing that was transformed into a mini Reptile House by Houck and other workers. The area had 16 boarded-up windows and the Oregon Zoo team overhauled the area, re-opened it in the 1970s with around 50 specimens and it remained open for a few years before closing permanently in 1980. The mini Herp House was transformed into an outdoor exhibit for Chimpanzees, which at that time were kept inside 24/7.
Houck also discusses working at the Feline House in the early 1980s, mentioning that the Amur Tigers were the first thing visitors saw as the zoo's entrance was placed differently back then. There were African Lions, African Leopards, Snow Leopards, Clouded Leopards, Red Pandas and Short-tailed Fruit Bats all found in the Feline House.
Two full chapters are perfect for zoo designers to read, as Houck goes into intimate detail about the planning and design of the AZA Best Exhibit Award Cascades Stream and Pond complex. It opened in 1982 and was the zoo's first brand-new exhibit since 1959. It's interesting to read about how the American Beaver exhibit initially had two major flaws (the sewer drain and filtration line were installed backwards (!!) and quickly fixed; but the lodge was built on the low side of the pond and the desired behaviours of beavers building a dam was never achieved due to that construction flaw). It's intriguing to read about the species in that area (American Beaver, River Otter, Oregon Red-spotted Garter Snake, Western Skink, Rough-skinned Newt, Red-legged Frog, Tailed Frog, Eschscholtz's Salamander, Pacific Giant Salamander, plus a variety of fish and some birds in a waterfowl aviary) and the zoo actually bred Water Ouzels/American Dippers but the single chick did not survive for long. It was apparently the first ever breeding in a zoo.