These are good ideas!.
Some of the lawns are of memory heritage listed, they havent changed since the zoo opened. Which is a good thing to keep. These are the places they should concentrate retaurants/food/beverages around and kids play areas. The views are fantastic, and it would free up other areas for development. If they were to move the tortoise up closer to ARC, i dont think they have any andean condor anymore, or if so are they still on display?. That would free up a quite large area of land as you stated. At one point it was slated to be developed into an elephant exhibit expansion. Now the zoo no longer houses elephants an expansion into orangutan/gibbons would be a fantastic use of the space.
However the current trend at Taronga i wouldn't expect them to be developed for anything animal related sadly. For the first time in a while the map actually has a fair amount of unused space between exhibits. Which is sad, when you think taronga has steep terrain something that would lend itself well to primates especially with mesh exhibits. Which is a theme they are using and looks quite good at the moment. They could easily incorporate the large trees without removing them.
Taronga still has Andean condor. They have a female, who was bred at Taronga Zoo to their retired breeding pair. I did read on here that two of her siblings have been paired up (presumably for breeding) given we can’t import the species. It would be a real shame to lose this species from the region after so many decades - this particular family line dating back to the 1940’s.
I’m very curious to see what eventuates with gorillas. There’s little to no chance of orangutans returning to Taronga; so an ongoing focus on gorillas (as well as chimpanzees) seems likely.Originally it was built because to many people living in cities had lost a sense of where food comes from. I remeber in 2010 at uni listening to a keeper talk about how adults were surprised to see milk was coming from. So back in that time period it was deemed necessary. It did indeed have a much higher guest engagement. However times have changed very rapidly, people are far more aware of food, there are far more food intolerances and vegan people around. The general public is much, much more aware of these things. Which takes BTB main attraction out of it.
It is close to Nura Diya, it would be nice to see the aussie natives retained and exhibits added at the back of Nura Diya added to them. But then it leaves a large area of BTB that could be redeveloped. If you look at BTB and the surrounding area, you could easily build the new gorilla complex, and then new pygmy hippo enclosures in that area and the surrounding areas, including the area Steve outlined above. Bonus points the gorillas and hippo can stay put while its developed and the development is basically for the most part out of the way.
If the zoo wished to retain a petting zoo. There is space around the tree tops area or where they currently keep the sheep in the old aussie exhibit area to have small one. But is it really needed, are kids learning about conservation and getting engagment with exotic animals if they are playing with barnyard animals.
Unless they give consideration to holding bachelor gorilla males at Dubbo, Taronga will presumably consider building new exhibits with the view of maintaining a bachelor troop alongside the breeding troop. The troop they have is cohesive for now; but given the age of the adolescent males, that’s testament to their personalities (and the tolerance of their father) as much as anything. Kibabu and Fataki clashed far more; though the culture was very different in their troop.

