With a population bottleneck of only 21 individuals, it sounds like their entire population is inbred. Even if it's hundreds of individuals now.
Seems you need more like thousands to ensure survivability, and it gets non-linearly worse as population gets smaller.
https://www.sciencedirect.com/science/article/abs/pii/S00063...
Same thing happened to Cheetahs and, to a greater extent, Florida panthers.
What a throwback. I haven't thought about the movie Fly Away Home since I was a child. Really awesome to see people caring enough about animals to do stuff like this.
Wow I haven't seen this movie in...about 30 years. We had it on VHS when I was a kid. Time flies.
Hah, was just about to write about that movie too :D