2 Colo. Code Regs. § 406-17-17166
The claimant must produce evidence establishing that gray wolves caused injury or death to livestock or livestock guard or herding animals. Evidence proving such causation may include the type and location of wounds or a physical description of the carcass, such as rake-marks and canine punctures on the hide, the measured distance between canine wounds, and hemorrhaging found underneath the hide.
The claimant must produce tangible evidence that gray wolves were present in the area, such as photographs of gray wolves, photographs of gray wolf tracks, or confirmed fur or scat samples. The claimant may also present evidence in the form of certified statements that gray wolves were in the area based on personal, firsthand observations.
2 CCR 406-17-17166