From the seat of a helicopter, Wyoming Game and Fish Department’s wolf specialist Ken Mills knew something was off when he counted far fewer wolves than projected.
January aerial flights are a biologist’s rite of passage to start each new year, when scientists take advantage of the end of the fall hunting season to take an annual census.
But this year looked a lot different.
“We have not recorded a disease outbreak that has caused a population level impact like we did this current year,” Mills told KHOL.
All it took was a blood test in a few recaptured wolves to find high levels of canine distemper, an aggressive measles-like disease that attacks an animal’s respiratory and gastrointestinal systems.
It’s the leading hypothesis as to why the wolf population on state-managed land is down to historic lows. The wolves that tested negative for the disease the last two years tested positive this winter, Mills said.
At 132 wolves, this year’s count rivals the numbers in the years after the feds began recovery efforts in 1995 for the apex predator. The state’s ideal number of wolves in the state managed “trophy game” management zone is 160. That’s the nearly 3 million acres of state land between Grand Teton, Yellowstone and the Wind River Reservation.
Wolf pups are, in particular, the most vulnerable to the disease. Only 37% are thought to have survived the last year, according to Mills’ recently published annual report.
“It’s the lowest number of wolves we’ve had since 2005,” Mills said. “So, it’s fairly significant.”
Mills said he’s never seen an outbreak hit wolves to this extent in his 18 years as the state’s leading wolf biologist. Nor has the state seen such a dip since taking over wolf management from the feds in 2002. It’s also the first distemper outbreak on state-managed lands.
But the disease is not new to the region. It has hit federally managed wolves in Yellowstone National Park at least five times.
“After one of these events, [wolves] tend to recover very quickly,” Mills said, referencing data from Yellowstone.
Mills’ report supports the theory that disease, including distemper, takes off after populations climb to carrying capacity.
In recent years, wolf numbers neared carrying capacity, or the state’s population objective, after low mortality rates in 2023.
Mills said the department’s goal remains focused on reaching the recovery objective of 160 wolves.
Hunting and killing wolves to control conflicts with humans, including protecting private property appear to have “generally held the wolf population below the threshold” where disease is more likely, the report said.
This year’s population setback could shape wolf hunting season.
The state has proposed cutting the wolf mortality limit to 22. That’s down half from last year.
The department is hosting a public forum on proposed changes, including wolf hunting season, on May 26 at its regional office in Jackson. The public comment period ends June 10. In most parts of the state, that season starts Sept. 15 and ends by the new year.
