Looking it up quick, successful hybridization, meaning the offspring can reproduce, seems very common in birds, with somewhere 10-20% of species being able to do it. I found one old study from the 70s putting mammals at 6% and birds for 10%.

I know animals like mules are typically infertile, and the fancy hybrids like zonkeys and ligers/tions are also. It seems to be the males of these hybrids that are infertile, females seem fine.

Sparred Owls, the hybrids of the Spotted/Barred pairings are usually killed when they do these programs, so I dont know how much they've actually been studied. They seem to have a mix of both physical attributes like coloration, a mix of spots and stripes, and also a mixed of behavior and calls.

I feel bad the headline is going to get not many people to click on it here, but that's the actual title of the article... I do think this is an important issue now and is only going to become more important in the future when the same is going to happen to other species if we can't pull the environment back and this starts to happen with more and more species.

The biggest downside to the hybrids will be if the hybrids are more successful than the actual Spotted Owls, if we magically come up with a solution/breeding program/environmental fix/genetic miracle, etc., how do we ensure we're "bringing back" the actual Spotted Owl.