This piece of equipment is used to find a bog turtle. It is one of the rarest turtles in North America. Craig Patterson works with the Maryland Department of Natural Resources. He is looking for a bog turtle that is carrying an antenna. Patterson says the creature must be close because sounds from the device are getting louder. More than thirty turtles are living under dirt in these few hectares of protected land.

The bog turtle is endangered in the United States. Only several thousand survive. They live in small areas of wetland like this one. Scott Smith has worked with bog turtles for seventeen years.

SCOTT SMITH: "This one has had a chronic problem with an ear infection."

This male turtle was first found twelve years ago. The turtle weighs one hundred thirty grams. The radio equipment on his back weighs only seven grams. It helps scientists study his health, behavior and resting places.

Smith says bog turtles spend a lot of time digging down in the dirt, opening up little spaces for other animals to use.

 Julie Slacum works for the United States Fish and Wildlife Service.

 JULI SLACUM: "Part of the issue is loss of the habitat, but part of the issue was people going into the wetlands, taking the turtles and selling them illegally."

 Scott Smith says other threats are a slow reproductive process and animals that eat turtle eggs. Land development and changes in waterways have affected the environment of bog turtles.

 Recently, environmental groups and local governments joined together to protect the creatures. Bill Branch is a biologist with Marylands Highway Administration. He says state officials planned to build a road in this area many years ago. But that was before bog turtles were discovered here. After the discovery, officials decided to move the road project. The road is now being built on the other side of the hill.

 There are also efforts to rebuild the turtles environment. Farm animals are now clearing invasive plants from the area. Officials are avoiding chemicals or machines that could threaten the turtles. I'm Doug Johnson.