Two of the nine surviving wolves transplanted to Colorado have mated. Their success means they’re officially a pack, known as the Copper Creek pack.

At least one pup was been born to a pair of wolves transplanted to Colorado from Oregon in December.

Colorado Parks and Wildlife on Thursday evening said a gray wolf pup was spotted on June 18 in Grand County but said it is likely as many as five more were born.

Biologists tracking location data noted in early April that a female’s collar had stopped uploading GPS coordinates, but then resumed sending data later in the month. This led the biologists to believe she was likely in a den.

Though CPW did not release a photo or video footage of the pup, a news release said biologists had observed the area where the female’s collar was transmitting from the air and ground, using remote cameras and public reports. The biologists will continue to observe the denning area to see if there are more pups. “It is possible that other pups may be present, as wolf litters commonly consist of four to six pups,” CPW wrote.

This is the first birth of a gray wolf since wolves were reintroduced at the direction of Colorado voters. At least three pups were born in Jackson County in spring of 2021 to a pair of wolves that migrated naturally into Colorado from Wyoming. That litter was the first in Colorado since the species was extirpated 80 years before.

Colorado voters narrowly passed Proposition 114 in November 2020, directing state wildlife officials to begin reintroducing wolves west of the Continental Divide by the end of 2023.

Because a pair of the 10 wolves released on state land has reproduced, that family group is considered a pack and has been named the Copper Creek pack by state wildlife officials. One of the transplanted wolves, a yearling female, was killed in Larimer County, likely by a mountain lion.

“We are continuing to actively monitor this area while exercising extreme caution to avoid inadvertently disturbing the adult wolves, this pup, or other pups,” CPW Wildlife Biologist Brenna Cassidy said in the news release. 

CPW also said it will work with landowners in the area to implement practices to minimize the potential for conflict. 

The reintroduction of wolves on the Western Slope of Colorado has been fraught with conflict, with ranchers in Grand, Jackson and Routt counties reporting at least a dozen cows and calves killed.

Since they were released in southwestern Grand County and at an undisclosed location in Summit County, GPS tracking data has showed the animals ranging as far west as Routt County, east into Larimer County and near the Boulder and Gilpin county lines, and north to Wyoming.