
With a pack established by two naturally migrating wolves and their litter of pups born in spring 2021 in Colorado, Colorado Parks and Wildlife (CPW) biologists were interested in the opportunity to use and add collars as a part of our gray wolf monitoring toolkit.
Although three total tracking collars have been on members of the known wolf pack in North Park, Colorado, the collars are no longer functional.
One very high frequency (VHF) collar was deployed on wolf F1084 in Wyoming in 2017. The battery on the collar had a lifespan of 5 years and is no longer functional.
Two additional collars have been put on wolves in northern Colorado by CPW staff. Wolf 2101 had a collar attached in the spring of 2021 and wolf 2202 received a collar in the spring of 2022. Both collars had GPS (satellite) as well as VHF (radio) technology. Disappointingly, the GPS and VHF functions on both wolf collars have failed.
What are GPS and VHF collars?

Developed in the 1990s, GPS collars have helped revolutionize wildlife monitoring and research because they collect (and store) a high quantity of location information. They also provide information about animal movement patterns and survival.
CPW has used tracking collars for numerous wildlife monitoring and research projects in Colorado, including elk, deer, and cougars. VHF and GPS technology can even be used for transmitters deployed on birds, fish, and reptiles.
For the wolves in North Park, the GPS technology collected location points at a predetermined interval, stored them, and then communicated the data via satellite to CPW biologists. (CPW did not know exactly where a wolf was in real-time. Staff could view the newly collected location data every few days.) VHF radio collar technology has been around since the 1950s and works by the collar emitting detectable radio pulses that are transmitted on specific radio frequencies. To locate the collared animal, biological staff use equipment to detect the intensity of the radio pulses to locate the animals in the field.
While useful, tracking collars have limitations and imperfections.
The lifespan of GPS collars (e.g., how long it is collecting data or transmitting a signal) depends on how much data is collected. Typically, collecting more data results in a shorter collar lifespan. The lifespan of a collar is often shorter than a wolf’s lifespan, but not always. Collars continue to collect data and can tell us when an animal has died (stopped moving), so even if an animal dies before the collar does, they are still collecting and transmitting important information.
Once on an animal, collars can fail for several reasons. For example, there may be manufacturing defects that cause the battery to prematurely fail, or the collar may stop communicating with satellites, thereby preventing GPS data from reaching biologists.
There is a tradeoff between the complexity of the collar and its longevity. The more technology that is incorporated into the collar, the increased likelihood of failure. Simpler collars may be more robust and have a longer lifespan, but limited functions (e.g., VHF only).
Additionally, collars get beaten up, chewed by animals, and can fail from being out in the elements on a wild animal.
Confirming collar failures can be challenging. Close proximity to the animal in relatively open landscapes are best for signal detection. It may require several attempts locating and detecting a collared individual to confirm its collar status.
There are no immediate plans to collar additional animals at this point in time. Using helicopters to capture animals in the heat of the summer presents logistical challenges in addition to concerns about animal welfare. Because gray wolves have been relisted under the Endangered Species Act, CPW will need to coordinate with the U.S. Fish and Wildlife Service to conduct future capture operations. CPW plans to deploy more collars in the future for research and monitoring. CPW also plans to collar all of the animals that are used in the active reintroduction.
Where do we go from here?
Although unfortunate, what happened with these collars is not all that uncommon. Importantly, CPW does not plan to collar all wolves in Colorado because it would not be possible, and collars will not provide real-time location information. This highlights the need to diversify wolf monitoring and research tools.
This experience also demonstrates that it is important to develop conflict minimization strategies and programs that are not entirely reliant on having collar location information.
To confirm a wolf sighting, field biologists rely on observations like signs of tracks and scat. CPW also has a wolf sighting form available on our website and we encourage people to fill it out if they believe they have seen a wolf in their area. We ask that any photos or videos be included with these reports if available.
Written by Travis Duncan. Travis is a public information officer for Colorado Parks and Wildlife in Denver. He has lived in Colorado for nearly 20 years and loves the outdoors.
11 Responses
interesting stuff,glad to have information
No offense but your plan in its entirety is a bad idea, and you cannot do this right. Why should we trust you with this wolf project or anything else?
Colorado is not the wilderness it used to be so why pretend that introducing wolves is appropriate?
They are smart, able predators that I do not want to meet on a hike. Why should ranchers and anyone else have to deal with wolves?
Proposition 114 – What Comes Next?
Proposition 114 (https://leg.colorado.gov/ballots/reintroduction-and-management-gray-wolves) – now state statute 33-2-105.8 – directs the Colorado Parks and Wildlife Commission to develop a plan to introduce gray wolves onto the Western Slope of Colorado, passed on November 3, 2020.
Statute directs the Colorado Parks and Wildlife Commission to:
– Develop a plan to reintroduce and manage gray wolves in Colorado no later than December 31, 2023, on designated lands west of the Continental Divide;
– Hold statewide hearings about scientific, economic, and social considerations;
– Periodically obtain public input to update the plan; and
– Use state funds to assist livestock owners in preventing conflicts with gray wolves and pay fair compensation for livestock losses.
At its January 2021 meeting the Parks and Wildlife Commission provided CPW staff with guidance to begin creating a robust, adaptive management plan to reintroduce wolves in Colorado no later than Dec. 31, 2023.
While CPW will continue its planning efforts to meet the deadlines directed by statute, reintroduction will require close partnership with the US Fish and Wildlife Service and will be subject to their approval. Their permitting requirements and processes will need to be followed as they now have management control of the species in Colorado.
Our Wolves in Colorado FAQ page provides the most current information available on the species and planning status. (https://cpw.state.co.us/learn/Pages/Wolves-in-Colorado-FAQ.aspx)
As hearings and public input opportunities are planned, CPW will communicate information about how to participate through our website, social media channels, and eNews newsletters. https://cpw.state.co.us/aboutus/Pages/socialmedia.aspx
To learn more please visit – https://cpw.state.co.us/learn/Pages/CON-Wolf-Management.aspx
The plan is good, and they are doing a good job implementing it (Hitchens’ razor). Many would like to meet them on a hike, so it’s good this isn’t about what you or I like or want. We entrusted DPW because they are the professionals, and that’s reason enough.
That Colorado is not what it used to be is irrelevant, but it wasn’t a wilderness when we extirpated wolves, regardless. And, until recently, Coloradans have been killing every wolf that wandered back into the state. You don’t have to deal with them (or anything, for that matter), but others will because it’s in their best interest.
Assuming I live long enough, I look forward to the day I might come across a wolf by chance, just as I have mountain lions and bears. Oh My!
It’s imperative to have two collars on every pack incase one collar fails. Every pack needs a functioning judas wolf incase the entire pack needs culling.
There were three on this one. As for the need for a judas wolf in every pack, I suspect you just wanted us to know you knew what the term meant.
Wolves as well as all animals have a right and a reason for existence. They play an important part in the balance of other species that also provide a necessary role in the overall health of our environment and our world. Man has played a disgusting role in annihilating any wildlife and also human races that do not suit their own needs and special interests. I would hope that kind of thinking is in the past. If a person wants to recreate in areas where wildlife exist, the recreator needs to take whatever precautions are recommended to fend off the potential threat.. Learn to live with all, use precautions and trust in God. Man is the only creature who kills for hate, fear and selfishness. Why doesn’t the Parks & rec enlist people people from extensions of .wildlife supportive clubs to get to know the various packs of wolves and try to keep track of their whereabouts. A worthy outing! Once they are familiar with the groups, such as in Yellowstone, they can keep and eye on them and any threats to their packs. People love to wildlife observe and would be a deterrent to offenders.
N J Animals have no rights, and they don’t even have a reason to exist. 75% of the large mammals in N America were wiped out before Europeans ever set foot on this continent, yet the ecosystem got along just fine without them. There is no balance of nature. It’s ok to say we want wolves in our state, don’t even need a reason, wanting them here is good enough, but making believe they are needed for reasons of ecosystem services is imagining.
Good point somsai. Tired of hearing about “pure ecosystems” myself. The whole debate is really about world views and not “science”‘.
To learn more about wolves in Colorado, please visit the CPW site – https://cpw.state.co.us/learn/Pages/CON-Wolf-Management.aspx. To stay current on wolf-related issues, please sign up for the wolf eNews – https://state.us10.list-manage.com/subscribe?u=5144ed31c5f2ba642e0393361&id=89503128b0