I was curious because I don't know much about the subject but, what animals are able to be released into the wild, coming from a captive background? If certain animals are not able to survive being released into the wild, do you think there is a possibility of making beyond suitable environments to train them to be more "wild" or at least give opportunities to train an animals offspring from the moment it's born? When I say train, I really mean no human interaction, just training by the environment they live in.
Several bird species, including the California condor and whooping crane, have been successfully raised in captivity and released into the wild. Black footed ferrets are one of the most famous examples of a species being restored by captive breeding. There are a lot of species where successful captive born release hasn't been done, or the success rate is rather low, (I believe this is the case for large carnivore mammals, feel free to correct me if I'm wrong) but I'm optimistic that more research into the subject can improve future success rates. Though there are some species where I don't think it could ever be done. Killer whales, for example. I do think that a captive born individual could learn to survive in the wild, hunt and avoid threats and all, but social life would be an issue. Wild pods usually don't have a very flexible social structure, so you wouldn't be able to count on a released orca getting accepted into a new pod. (the fact that orcas have "regional dialects" would make it even harder. Would they even be able to communicate?) Releasing captive orcas would probably require you to raise like, an entire pod at a time and release them all together, that would be very impractical.
It is a big story. Animals which operate instinctively, like insects, fish or reptiles are easy. Birds and mammals which can be trained to be wild and which don't have many natural predators and don't migrate are easier. Going to what MightyOrca said, while California Condors and Whooping Cranes were brought back, they were intensively trained and many individuals died or had to be recaptured. California Condors, for example, had to be trained to avoid people, not to perch on electricity pylons, not to go to sleep on the ground, and all have to be recaptured briefly every few months to see that they did not eat lead bullets with their carrion. Only young condors can be released, adult birds all perished soon after release. Whooping Cranes had to be taught to migrate by means of an aircraft, to avoid people, and to avoid places and times where predators can catch them. Both these have interesting and very entertaining blogs of teams which re-introduce them. Some other examples: for example released killer whales never integrated into wild pods of whales and remained where they were released. Teaching orangutans and chimpanzees to be released in years-long job. Released capuchin monkeys are usually attacked and killed by resident wild monkeys, if they occur in the area. Released red-shouldered parakeets died from hawks and ringtails. Their release was abandoned, It was concluded that the only way to teach them would be to catch some wild parrots to act as role models, but this was counter to the purpose of releasing them.
I think its also important to realise that the idea of releasing captive bred animals into the wild intentionally as part of population restoration measures is a very new idea. Sure animals were released in the past, but it wasn't really with the intent of bolstering wild populations and as a result wasn't studied after the release much. So I would say there's still a huge amount that we have to learn, though I think its very valuable information as well. It forces us to study animals to a much greater level, to really understand their language, their learning process, their survival and how they live in the wild. It really highlights that humans are not alone in having a learning phase and firmly kicks the "animals are all instinctive" idea out the window. I also think its important to identify that re-introductions are only as good as the environment they are released into. If threats such as population isolation; poaching; habitat loss; pollution; excessive predator pressure; climatic change et c.. are still present then reintroductions can only, at best, prop things up. Of course there's a difficult part where you have to decide on if you keep reintroducing and hope that you can prop things up for long enough to maintain a wild population whilst you continue to battle the other pressures; or if you run the risk of losing the wild population but maintaining a captive one for a longer term release in the future. For zoos, who have display as one of their primary features, release is also difficult because its a totally different approach to captivity. Release individuals generally have to be kept away from the public, in different kinds of enclosure and have to be, as said above, trained and prepared for life in the wild. You also often need a captive site in the release area or at least the release environment in order to prepare those animals for release into the area where they are to live - especially if your release individuals are being raised hundreds or even thousands of miles away in different countries and climates
Sorry if I was unclear, I think I forgot to write it down but I meant in a hypothetical situation if we ever reached the point were habitats would be restored and safe. Other than that, I completely agree with your statement about how tough it would be. With the support for the environment and animals nowadays, it makes me wonder how much potential the zoological community has in order to reintroduce species back. It would be so expensive, but at the same time it's a necessity to rehabilitate earth. The thought popped in my mind because I was talking to an employee at the San Francisco Zoo yesterday about their lemurs and somehow, we started talking about duke university and their program. I was so captivated because she said their are plans to release them later but for now they are working their best to restore the environment and to educate in Madagascar. One way the San Francisco Zoo is doing this is by vaccinating chickens and sending them to villages for food so the lemurs aren't hunted for bushmeat. Also for their training program at Duke, she said what they do is they create habitats with Fossa scents in order to make it familiar with the individuals they have. Makes me wonder if they will do this at the SF zoo when they get their fossa exhibit.
Reintroductions are certainly a long term project and as you've discovered any program within a zoo has to tie into an in-situ one in the environment they are destined for. Zoos do have potential, when managed over international or at least national (for large nations supporting multiple zoos) to maintain captive populations in viable breeding conditions. As a result if the restoration/protection of the environment takes too long the zoo system can preserve a species. Of course unlike plants one can't just put the seeds into storage and wait - you've got to keep them alive. That's a huge ask when there are a lot of endangered species - so its a lot of pressure.
All good points. This is, again, why I'm optimistic for the future of captive releases. There's still so much to learn, the possibilities may be greater than we know. Though as Jurek7 says, successful release requires a lot of hard work. The environmental protection thing is also why I get pretty miffed at people who act like captive breeding is the only way to save species. You could have a captive breeding and release program with a 100% success rate, but it's not worth much (if anything) if there's no suitable, safe-from-human-activity environment for them to return to. (that, and the fact that some species will never be suitable candidates for such a program)
Speaking of orcas, just remember the true story of Keiko, who was starved during his "conditioning" to the wild and deprived of human attention, then was thrown out in the wild only to never integrate into a pod, only to be found interacting with humans at a nearby village and to starve himself to death (along with pneumonia) just a few months later.
