A fourth gray wolf that was brought to Colorado from Canada as part of the state's reintroduction program has died, Colorado and federal officials confirmed on Friday morning.
This wolf was a female and died in northwest Colorado in an unknown location on Thursday, Colorado Parks and Wildlife (CPW) and the U.S. Fish and Wildlife Service (USFWS) said.
As with any wolf death in Colorado, the USFWS is investigating because gray wolves are a federally listed species under the Endangered Species Act. The USFWS will determine its cause of death. That investigation is ongoing.
No other details were available from either agency.
Fifteen wolves were brought to Colorado from Canada in January 2025 during the second round of reintroductions. As of publishing time, two males and two females have died:
- March 16: A male wolf was killed by Wildlife Services in Wyoming after it was found at a property where multiple sheep had been killed earlier that day
- April 9: A male wolf died after traveling into Wyoming
- April 20: A female wolf died in Rocky Mountain National Park
- May 15: A female wolf died in northwest Colorado (this story)
In the past, CPW has stressed that wolf survival in Colorado is currently within normal margins and that mortalities were taken into account when building the 261-page Colorado Wolf Restoration and Management Plan.
In the short-term, the reintroduction program will be considered successful if the survival rate is high, the wolves stay in Colorado, packs form and breed, and if wolves born in Colorado survive and go on to reproduce, according to that plan. The plan appears to read that a survival rate of less than 70% within those six months would initiate a protocol review, as screenshotted below.
Denver7 contacted CPW on Friday to learn more about what a possible protocol review would look like, since 11 surviving wolves out of 15 hovers around 73%. However, a spokesperson said the 70% survival rate outlined in the plan is only applicable to the capture, transported and release of the wolves, and not the mortalities that occur afterward.
Colorado's wolf reintroduction management plan lists the goal of translocating 10 to 15 wolves per year for a total of 30 to 50 wolves over three to five years. After that point, the active reintroduction efforts will stop and CPW will focus solely on monitoring to see if the population is self-sustaining.
Read the full wolf restoration and management plan below or here.
As of Friday afternoon, the number of known wolves in Colorado is as follows:
- 7 wolves surviving from the original 10 that were released in December 2023 (one died of a likely mountain lion attack, a second died from injuries sustained prior to his capture as part of the Copper Creek Pack relocation effort, and a third wolf became sickly and died)
- Five wolf pups born in the spring of 2024
- 11 wolves surviving from the 15 that were released in January 2025 (one was shot and killed by Wildlife Services in Wyoming earlier this month, a second died of unknown causes in Wyoming, a third died in Rocky Mountain National Park, and this story is about the fourth death)
- Two wolves that moved south from Wyoming several years ago
- One uncollared wolf that was last known to be in northwest Moffat County in mid-February. It is not clear if it is alive or still in the state.
- Possible, but unconfirmed, wolf in the Browns Park area
Below is the most recent map of the wolves' movements around Colorado. Officials at a recent CPW Commission meeting were quick to note the eastern-most watershed — which encompasses Ralston Creek — and appears to have a finger reaching into western Denver, saying that the animal was "in the very far western portion of that watershed."
Want to learn more about Colorado's wolf reintroduction? You can explore the timeline below, which outlines all of Denver7's coverage since the very beginning. The timeline starts with our most recent story.