Endangered turtles bred at Brookfield Zoo released into DuPage wild

The tiny turtle squirming in Dan Thompson's hands looks like a content creature.

The shape of its mouth gives the appearance of a smile and the impression that the young reptile is blissfully unaware it takes a village to reach this rite of passage.

Every fall, Thompson wades into knee-deep, murky water to release Blanding's turtles into the marshes of the Forest Preserve District of DuPage County. After a year in captivity, the turtles have grown from quarter-sized hatchlings to plucky juveniles, eager to experience the natural world.

Each youngster carries a spotted shell and the hopes of conservationists who have spent 25 years working to offset population losses.

“They're all special, really,” said Thompson, a district ecologist.

But the batch released Wednesday are unique in their own way. They are the first Blanding's turtles bred and hatched at Brookfield Zoo's captive breeding pond, a genetic reservoir built with females from the forest preserves.

“We're just very happy to see them move on and contribute to a population,” said Andy Snider, the zoo's curator of herpetology and aquatics.

Brookfield contributed 10 turtles to Wednesday's release, while another dozen from the Peggy Notebaert Nature Museum in Chicago ventured into grassy marshes.

The species is endangered in Illinois, under threat from habitat loss and fragmentation, predators, roadside mortalities as females cross traffic to get to nesting sites, and an illegal black market. The forest preserve district doesn't disclose the exact location of their release to protect the turtles from collectors.

District ecologists launched the species recovery program in the mid-1990s after observing a troubling population decline. Older generations outnumbered more vulnerable, younger turtles as raccoons and other midlevel predators flourished with suburban sprawl.

“We were dealing with a really small population of wild adult turtles, and that's all we had,” Thompson said. “We did not have any kind of age structure.”

The district tracks turtle births with radio transmitters attached to females. When they're ready to nest around early June, ecologists bring the turtles to Willowbrook Wildlife Center in Glen Ellyn so the reptiles can lay their eggs away from the threat of raccoons.

After an incubation period, the hatchlings spend about a year at zoos, museums and other partner institutions until the turtles are large enough to have a better chance at survival in the wild.

Then the process starts all over again. A slowing-maturing species, Blanding's turtles don't start reproducing until their midteens to their 20s.

“We've been fortunate that we've hit that threshold, and we've actually had some of our head starts in the wild survive to maturity and are reproducing and providing our third generation of turtles now,” Thompson said.

In 2011, Brookfield Zoo began to develop a breeding pond to produce captive-bred youngsters to send into the wild. Last year, some of the nearly 25 females in the pond were old enough to successfully breed and lay fertile eggs in a nesting beach.

In the spring and summer months, the zoo also uses outdoor enclosures in Dragonfly Marsh to “head start” the district's hatchlings.

Nearly 3,500 turtles have hatched out since the inception of the forest preserve district's program.

Ecologists hope that eventually, the region will see signs of a self-sustaining population, but conservation efforts take time. They keep at it knowing that their work preserving the Great Lakes native supports biodiversity.

“We're really certainly at a time right now that we really need to be much more vigilant about how we care for the planet and how we live to make sure that we have less impact,” Thompson said.