(CHICAGO) Eleven ornate box turtles — a Midwest species that has come under threat in recent years — were reintroduced to their native habitats Wednesday thanks to a conservation program at the Lincoln Park Zoo.

To help the population thrive, ornate box turtle eggs are collected and brought to the North Side zoo where they can incubate and hatch far from the usual threat of coyotes, snakes and raccoons.

When the turtles are about a year old, zoo officials return them to their native habitat in the Upper Missouri River National Wildlife and Fish Refuge, according to the zoo.

The 240,000-acre refuge runs along the river bordering Illinois, Minnesota, Wisconsin and Iowa, according to the U.S. Fish and Wildlife Service.

“Tracking the turtles is an essential part of this population restoration effort,” curator Diane Mulkerin said in a statement released by the zoo. “The GPS signal enables researchers to find not only the turtles, but their nests, so nests can be protected and eggs can be collected for head starting.”All of the turtles have unique markings and radio transmitters to help curators research and track them.

The program hopes to bring 100 more turtles to the habitat by 2020, the zoo said. In addition to the ornate box turtle program, the zoo participates in conservation efforts for other threatened and endangered species, including meadow-jumping mice, smooth green snakes, wolves, swans and other species in Illinois and across the U.S.The 11 turtles reintroduced on Wednesday were released in habitats near Thompson Sand Prairie in Thompson, Ill., and Lost Mound in Savanna, Ill., both of which are within the larger wildlife refuge.