Dan Vergano reports for USA TODAY. Follow the link below for photos and other relevant materials.

Endangered species success stories are just about the only things more rare than the world’s threatened wildlife.

But one Caribbean species, the Blue Iguana of Grand Cayman island, found nowhere else in the world, is looking like that rarest of things, a threatened species roaring back from the brink. Once down to perhaps less than a dozen animals, the long-tailed lizards, some growing to five feet and weighing 30 pounds, now number about 500, suggests a tally from a weeklong health screening that ended July 3.

“They are striking animals, turquoise blue with red eyes, they have an almost noble way they hold themselves,” says conservation biologist Fred Burton, head of the Blue Iguana Recovery Program. “But they were almost a forgotten animal.”

Biologists knew about the animal, with an Oxford University expedition first describing them scientifically in 1938. But they had disappeared from the island as farmers planted more land and roads stretched across the island as well. Farmers’ dogs killed the lizards and cars ran them over as they basked on the asphalt. “Cats, feral cats, were really the problem, we have them everywhere and these are very hungry animals,” Burton says. The cats ate young iguanas in droves.

But biologists didn’t know how bad things had gotten for the blue iguana until 2002, when Burton implored his colleagues meeting that year on the island for discussions of iguana conservation across the Caribbean, to stay and craft a conservation plan for Grand Cayman’s own native lizard. To do that, they needed to survey the population. And that’s when they realized they had a big problem.

“We just weren’t seeing any. And the ones we were seeing were far apart from each other, which isn’t what you want for mating,” Burton says.

“There was a sort of ‘oh no’ moment,” says Paul Calle, zoological health director for the Bronx Zoo-based Wildlife Conservation Society’s Global Health Program, one of the partners in the recovery program. “They quickly realized they had to do something.”

That something was captive breeding, Burton says, done with a purpose. “We didn’t know how they lived or what they ate.” So, his team started rearing its own iguanas, keeping them to various ages, letting them go and tracking their behavior. “We learned a lot. We had been feeding them rabbit food basically, all wrong, and keeping them in pens that were too small,” he says.

Blue iguanas eat all sorts of vegetation, but they really like fruit, it turns out, which was part of their downfall. They had congregated within fruit orchards, which the dry scrub land they called their home was becoming on the island. But there they met farmers’ dogs and cats.

Along with learning how to rear blue iguanas, the team learned when to release them, at two years of age, big enough to fend off the feral cats. And they found a place to put them, in two reserves without roads or farms, but with the dry scrub favored by the lizards. “They lay a lot of eggs, which is another thing in their favor,” Burton says. “Many of the ones we released are now reaching breeding age, so their numbers should really grow.”

At the health screening, which checked out captive-grown lizards prior to their release, “I saw more blue iguanas in one day than the entire species possessed less than a decade ago,” Calle says. “It is a remarkable turnaround.”

Burton concedes that the lizards benefitted from circumstances that other endangered species lack. Their hard-wired habits allowed an easy transition from captivity into the wild, for example, while large egg clutches let the conservation team raise many iguanas. And this year the conservation trust secured a second blue iguana redoubt, the Colliers Wilderness Reserve, for their preservation.

Within two years, the project estimates the iguana’s numbers will top 1,000, the target set for their recovery almost a decade ago. The challenge will then be not letting the problems that clipped their numbers before once again take their toll, Calle says. Instead of breeding captive lizards, recovery efforts will have to turn to keeping the reserves open to tourists, but not feral cats.

On the plus side, everyone on Grand Cayman, which is just south of Cuba, knows about blue iguanas now, which should make such efforts easier, Burton says. “They are quite the mascot of the island. We have stores named after them and cruise ships stop to see them. I think everyone here is quite proud of them.”

For the original report go to http://www.usatoday.com/tech/science/columnists/vergano/2011-07-16-endangered-blue-iguana-conservation_n.htm