Wolf OR-7 and his mate appear to be trying to add to their now-famous pack in eastern Jackson County.

Biologists say the alpha male and female of the Rogue Pack appear to be denning in high-elevation U.S. Forest Service land east of Butte Falls and Prospect.

The pair denned last year and successfully had three pups that apparently survived 2014 to earn the official designation as a pack by the U.S. Fish and Wildlife Service.

Oregon Department of Fish and Wildlife biologists say they are not 100 percent sure OR-7 is in the midst of fathering a second round of pups, but the wolves' recent lack of activity seems to point that way.

"Since we suspect they're denning, we won't go in until after May or into June to confirm it," says Mark Vargas, ODFW's Rogue District wildlife biologist.

Michelle Dennehy, ODFW's wolf program spokeswoman, says agency biologists plan to conduct their annual pup surveys in late June.

State and federal biologists since early May also have been trying to get a new GPS collar fitted on OR-7 or another member of the pack, Vargas says.

OR-7's collar enabled biologists and others worldwide to track his famous journey from Northeast Oregon into Western Oregon and across Northern California in 2012 and 2013 before he settled down with a pack in eastern Jackson and western Klamath counties.

The GPS component of that collar is dead, and it now sends just faint electronic signals biologists hope to pick up with a radio receiver to find, capture and collar one of the animals, Vargas says.

The pack's name is derived from the upper Rogue River watershed and the Rogue Wildlife Management Unit in eastern Jackson County, where the wolves spend the majority of their time in the South Cascades.

The Rogue Pack is one of 10 Oregon wolf packs. Also documented are six known pairs of wolves in the state, including two now in the Keno area south of the Rogue Pack's most common haunts. Oregon had a total of 77 known wolves at the end of 2014, according to ODFW statistics.

OR-7 was a young member of Northeast Oregon's Imnaha Pack when he was collared in February 2011, eight months before he left the pack in a "dispersal" trek in search of a mate and new territory.

He traveled south and west until he crossed the Cascade crest, becoming the first wolf in Western Oregon since 1937. He later spent more than a year traveling in Northern California, where he was the Golden State's first known wolf since 1924.

For close to two years, he has stayed within his home territory of eastern Jackson, western Klamath and southeastern Douglas counties, according to ODFW.

Reach reporter Mark Freeman at 541-776-4470 or mfreeman@mailtribune.com. Follow him at www.twitter.com/MTwriterFreeman.