Last week, over 20 scientists came together to oppose Colorado Parks and Wildlife’s (CPW) two carnivore killing studies. These proposed studies, one in the Piceance Basin and the other near the Upper Arkansas River, would kill large numbers of mountain lions and black bears in a misguided attempt to increase mule deer populations in Colorado.

Shocked by these studies, I contacted Adrian Treves, Ph.D., whom studies carnivore coexistence at the University of Wisconsin-Madison. I asked him to look over the proposed studies. He quickly got back with me, criticizing the low standard of scientific inference being used by CPW. Dr. Treves explained that the studies lacked the “gold standard” for scientific inference. This gold standard is the “random assignment to control and treatment groups with experimental designs that avoid biases in sampling, treatment, measurement, or reporting” (Treves).

Dr. Adrian Treves

Simply stated, these two CPW studies are poorly designed and will offer NO valid conclusions at the expense of wild lives and public resources.

In a detailed letter sent to the CPW Commission last week, Dr. Treves and the 20 signatories explain that these studies lack a proper control (an unaffected area that can be used for comparison), that there was bias when the killing sites were selected (the Upper Arkansas River study directly says the “analysis unit… was identified as an area where cougar suppression could be beneficial to the deer population”), and that the sample areas are too few to get any reliable statistical information.

He concludes by saying:

“Wildlife are a public trust asset and the proposed studies preferentially serve a narrow community of mule deer hunters and cougar hunters, while ignoring the broad public interest in healthy ecosystems, unimpaired wildlife populations, and transparent accounting for wildlife assets. If CPW is held accountable in court or by the legislature for its management of cougars and black bears, the proposed studies will not survive the legal test for a prudent trustee of the public interest in wildlife.”

The Commission has yet to formally respond to this letter. That’s why we need your help.

On December 14th, the CPW Commission will approve or deny these scientifically weak and invalid killing studies at a public meeting in Fort Collins. You can ensure that these studies get denied by attending this meeting on Wednesday, December 14th at the Fort Collins Marriott (350 East Horsetooth Road, Fort Collins, CO 80525) from 8:30 AM to 12:45 PM (RSVP HERE).  There will time for public comment and we must have our voices heard.

I’ll see you there!





Treves A, Krofel M, McManus J. Predator control should not be a shot in the dark. Front Ecol Environ. 2016;14:380–8.



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