Oh I am well aware of that. I keep dart frogs.
But even captivebred and raised frogs are not non-toxic. They are just significantly LESS toxic than their wild counterparts. I still wouldn't want to risk my cat eating an escaped frog. I don't keep any golden dartfrogs (Phyllobates terribilis),
so one frog probably would not kill her, but I doubt it would do her any favors.
And if you were trying to faithfully recreate a South American rainforest environment, that might include introducing appropriate native prey for the frogs to hunt, so they could accumulate toxic alkaloids for protection, which is what I meant by "maximum realism"
Beyond the issue of predation/poisoning, there are a couple other problems with keeping dart frogs in a parrot aviary that I can think of, based on what I know from my own experience. First, you would need to be able to meet the housing requirements for poison dart frogs in the aviary.
Depending on where you live, this could pose a significant challenge, especially in winter. Dart frogs do not tolerate cold or dry conditions. In many parts of the world, this means they would need to be kept in a climate-controlled environment, like a terrarium or greenhouse, rather than exposed to normal outdoor weather. So the giant rainforest-themed aviary would need to be fully enclosed and able to maintain warm, humid tropical conditions year round, even in the dead of winter.
On the upside, you would be able to grow all kinds of neat tropical plants in a climate-controlled greenhouse/aviary which your parrots would appreciate. On the downside, it would be expensive to build and also expensive to heat in winter or cool during summer. If you were building a normal parrot aviary without the full rainforest environment, you would still need to provide the birds with shelter during winter, but you would not need to heat the whole space. Many aviaries are designed to have a large outdoor area for flight and exercise, adjacent to an enclosed area that can provide shelter for the birds during bad weather. But if you plan on keeping dartfrogs in the aviary, that style would only work if the aviary was built somewhere tropical.
Second ... dart frogs are small. Really small.
This is my dart frog display terrarium.
It is 4ft by 2ft by 2ft which is quite big for dart frog enclosures, but tiny compared to a football field.
Can you find the frogs?
There are twelve of them in this tank. On a good day, I see three or four at the same time. Sometimes I can't find any. I know they are in there ... somewhere ... I just can't find them. Despite their bright colors, you have to really look to spot them, because they are so small and quite good at hiding under leaf litter. And I keep relatively large and bold dart frogs that were carefully selected to be able to handle living in a group as adults. Many species are even smaller and more shy. And most frogs prefer to live in mated pairs with their own territory, rather than hanging out with lots of other dart frogs.
I am trying to imagine how many dart frogs you would need to put into a one acre terrarium so that you would even notice they were in there .... it would have to be a ton of poison dart frogs. Way too many, actually. Because most dart frogs are quite territorial and get stressed out by sharing space with too many other frogs. Trying to find a balance between enough tiny frogs so you can even tell that that they are still alive and too many frogs would be a real nightmare.
On a related note, many dart frogs are "terrestrial" so they tend to spend the majority of their time at ground level. Which basically means "foot level" for a one inch tall frog in a large aviary. Aside from aviary birds eating the dart frogs, there will also be the risk of visitors stepping on them by accident or walking by them without even noticing, because they are under a leaf.
If you do manage to establish a large population of dart frogs in your aviary, how would you even feed so many frogs? Or check on them to ensure they are healthy and active? Or provide them with the mineral supplements they need to thrive on a captive diet? Also, are you going to just keep one species of dart frog or multiple species?
I assume you will want lots of different colors, so probably multiple species. Breeding will increase competition, stress, and aggression between the frogs which isn't great for their health And if they do reproduce successfully, your frog population could easily get out of control without careful management. It is also worth mentioning that many dart frog species are closely related. They can cross-breed to create hybrids which isn't great for their genetic diversity and species conservation. And it makes it difficult to find new homes for the hybrid babies, if necessary.
Like parrots, dart frog enthusiasts tend to keep their frogs in species-specific enclosures that are tailored to the individual needs of the specific frog, rather than larger multi-species terrariums. Mixing species can be done, but you need to choose your frogs carefully, monitor closely and be prepared to rehouse frogs if they are showing signs of being bullied or stressed. It isn't recommended for beginners, because you need to know the frogs and each species requirements pretty well to recognize a problem early enough to fix it before the frog dies from stress.
It wouldn't be as simple as releasing a couple of frogs into the parrot aviary and hoping some of them managed to avoid getting eaten by the birds.