MICHIGAN - The state Department of Natural Resources has outfitted black bear sows with radio collars so biologists will have an easier time helping orphaned cubs find new homes.

The denned sows are given collars so wildlife officials can track them down if orphaned cubs are found.

"You can trick females into taking additional cubs if it's done right," DNR wildlife biologist Mark Boersen said.

"The main objective has always been to have a number of female bears we can use to raise cubs that come into the possession of the DNR," he said.

He has collared several bears this winter season as part of the DNR's Surrogate Sow Program.

He said orphaned cubs are placed with new mothers once or twice a year. Placing cubs with adoptive mothers gives them the best chance at survival.

"It at least gives them a chance they wouldn't have and it works nearly 100 percent of the time if you can place the cub with a denned sow," he said.

Boersen started the season with two collared bears but has since collared three more.

He counts on landowners and hunters to alert him to bear dens.

In one case, a property owner in the fall saw a bear with two yearlings staying near an uprooted tree. He saw them again during deer season and contacted Boersen.

A grouse hunter's hound pointed to another den, underground.

Boersen collared the bear a few weeks later, and the sow and her cubs returned to their den.

Yet another den was found after Willy Hincka, a logger who lives in Presque Isle County, saw a bear before it hibernated and told the DNR.

When Boersen finds sows with yearlings, he sedates the mother bear with a jab stick but leaves the cubs alone. They either stay in the den or run around, returning once the commotion ends, the DNR said.

The sows are also given a full physical, which includes pulling a tooth to determine age, ear tags and lip tattoo, along with administering antibiotics and pain medication before putting the bear back in the den.

Cubs are also examined. They are kept warm, often in a workers' coats.

Boersen said one of the bears he has collared is 21, but they have been found in the mid-30s in Michigan.

Kevin Swanson, a wildlife management specialist with the DNR's bear and wolf program, said: "Bear den checks and other ongoing bear research in Michigan provide biological insight for wildlife personnel who face difficult management decisions for this valuable species."

John Agar covers crime and other issues for MLiveE-mail John Agar: jagar@mlive.com and follow him on Twitter at twitter.com/ReporterJAgar