GRANTS PASS, Ore. — While Washington state has set out to exterminate some members of a wolf pack that have attacked sheep in Eastern Washington, biologists in Oregon are still working to re-establish wolves in parts of that state.

As part of that effort, they are trying to put a new GPS tracking collar on Oregon’s famous wandering wolf, OR-7, so called because he set off in search of a mate in September 2011, covering thousands of meandering miles from his birthplace in Northeastern Oregon to Northern California before settling in Southwest Oregon.

Against the odds, he found a mate last winter, and the pair had pups.

The effort to locate OR-7, though won’t be easy. Biologists could be camping out in the Southern Oregon Cascades for weeks before they are successful.

U.S. Fish and Wildlife biologist John Stephenson says the upcoming operation involves setting out leg-hold traps with padded jaws in likely locations, then checking every morning to see if a wolf has stepped into one — a process that could take weeks.

“The capture is not all that glamorous a thing,” he said. “It usually involves a lot of days of getting up at the crack of dawn and going out and finding nothing in the trap.”

The morning they do find a wolf in the trap, biologists will use a syringe mounted on a pole to inject a tranquilizer to immobilize the wolf, weigh it and take a blood sample, all the while monitoring its vital signs to be sure it is OK.

If it is OR-7’s mate that steps in the trap, the blood sample could reveal what pack she is from through DNA analysis.

If it is one of the pups — biologists believe they should be big enough that they won’t be hurt if they step into one of the traps — biologists will continue trying to catch an adult.

If OR-7 hadn’t found a mate, no one would be trying to put a new collar on him, Stephenson said.

Though the public has been fascinated by OR-7’s movements, wildlife managers are more interested in the movements of his pack. Oregon’s wolf-management plan calls for collaring at least one individual from each pack.

And if they make it into winter with a pair of surviving pups, they will be the first pack in Western Oregon in more than half a century. Besides offering data on their habits, locations are vital in determining whether they have attacked livestock — something OR-7 has yet to do.

Rob Klavins of the conservation group Oregon Wild said people have mixed feelings about collaring wolves.

Wolves have died in collaring operations, and while collars help scientists understand wolves better, collars make it easier to track wolves down if they prey on livestock.

Information from The Seattle Times archives was included in this report.