A second group of wolves has been released in Colorado as part of a controversial, voter-driven initiative to reintroduce the predators to the state. Fifteen gray wolves from Canada were set free in the central mountains over three days last week,

This week, more wolves were released in Colorado as part of an initiative to reintroduce the species to the state. The gray wolf has been endangered in the United States for many years, and recent poaching and habitat loss have further diminished their numbers.

Colorado wildlife officials released 15 wolves from Canada into the central mountains over the last week as part of the second wave of the state’s historic, voter-mandated reintroduction of the native predator.

The controversial effort to bring gray wolves back has had mixed success. Of the first 10 wolves brought in from Oregon, dubbed the Copper Creek pack, just six remain in the wild, with one having been recaptured and three killed, Coloradoan.com reported.

Officials with Colorado Parks and Wildlife announce they have completed the second year of the wolf release program by

Fifteen wolves from British Columbia were released from Jan. 12 to Jan. 16. CPW also rereleased five members of the Copper Creek pack that they captured last year.