Think back only one short month ago. When the U.S Fish & Wildlife Service (USFWS) determined that dwindling populations of wolverines in the contiguous United States warranted listing them as “threatened” under the Endangered Species Act (ESA), seemingly everything changed for these tenacious creatures of the high-country. Yet, following the gleeful relief that court battles were finally over and the wolverine would now be legally protected, a more sober-eyed view offers a far murkier and uncertain path toward their recovery.

The “4(d) Rule” in the Endangered Species Act says that the USFWS must use the best available science to make “regulations necessary and advisable to provide for the conservation of a species.” Those regulations govern any actions, called “take,” that would “harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect” a protected species. However, certain activities can be legally exempted from those provisions. 

Unfortunately, after citing other direct threats like climate change, road-building, and winter recreation, the USFWS decided that “incidental” or “nontarget” catch of wolverines during legal trapping of wolves and other furbearers (like bobcats and foxes) will still be allowable and would not “significantly impact” wolverine populations.

The Idaho Conservation League has serious concerns about what appears to be arbitrary justifications used to make these blanket exceptions, given the well-known fact that trapping in wolverine habitat poses great threat to these rare and highly vulnerable animals. Had the USFWS made the completely justifiable decision to list wolverines as “endangered,” rather than “threatened,” those exceptions wouldn’t even be allowed.

Wolverine carrying a fish. Ed Cannady photo

Trapping regulations in Idaho are among the most liberal of all western states, and fall far short of doing everything possible to minimize incidental catch of wolverines. In 2021, SB 1211 encouraged the proliferation of trapping in Idaho, allowing IDFG to substantially expand seasons and methods to kill wolves. Idaho now allows wolf trapping and/or snaring for over six months of the year in 97 of 99 Game Management Units. Both of those practices have been documented to catch and kill wolverines, as wolves can occupy habitat used by wolverines all winter long. 

Additionally, the USFWS found that 48-hour trap check requirements “limit the ability for traps to be set in a wolverine’s range and allows for prompt trap set modifications or removal if signs of wolverine presence are detected.” However, Idaho only requires a 72-hour trap check, potentially leaving a wolverine trapped for 3 days before it can be released (if still alive). USFWS’ “guidance” for snaring operations suggests loops be set 18”-21” above the ground—presumably above the head of a non-target species such as a wolverine. However, should the trap site receive a foot of snow, that loop height can easily shrink to only 10-12”. Also, wolverines are excellent tree climbers and stand on their hind legs to satisfy curiosities, placing their heads well above the guidance height of 18-21.”

Furthermore, in Idaho, there’s not even a requirement that trappers report instances of the live-release of a non-target species, such as a wolverine. We also don’t know what injury rates are for incidentally trapped wolverines or how many actually survive after release. Gangrene (when a loss of blood supply/flow causes body tissue to die), broken bones and teeth, lost toes, and/or “wring-off”—when an animal chews off an appendage to escape a trap—are all traumatic injuries that could cause delayed mortality when an animal is released after an incidental trapping event.

The USFWS reports that 14 wolverines were trapped in Idaho over the last 20 years, but alarmingly, 70% of those events have occurred in the last five years. This coincides with the liberalization of trapping seasons and, paradoxically, the first time that IDFG imposed mandatory trapper education classes.

Because wolverines are consummate scavengers, living by their noses, their purpose in life is to find and investigate everything. They’re highly inquisitive and have been known to climb to the tops of mountains in the middle of winter—perhaps just to test for scents of animal carcasses. They’ve evolved to understand that there are payoffs to search out every oddity. Unfortunately, that makes them highly vulnerable to bait and attractants used at furbearer traps. Their persistence has been demonstrated in research studies in Glacier National Park and on the Sawtooth National Forest, where, even after an animal was caught and released, its bad experience did not prevent it from being recaptured in the same location—sometimes on the same day. 

IDFG needs to take every measure available to adjust trapping rules to minimize harm to wolverines, otherwise that activity will continue to pose significant risks to Idaho’s wolverines. Trapping regulations in Idaho are one of the only management tools we can adapt immediately in the wake of the wolverine listing decision that will have a concrete, beneficial effect by not removing animals from the population.

Wolverines spotted in the White Clouds in July 2020. Daniel Todd photo.

Wolverines have huge home ranges of up to 500 square miles. They crisscross large areas in pursuit of food, denning habitat, and to disperse into adjacent unoccupied territory. They also exist at extremely low densities. The USFWS’ 2023 Species Status Assessment estimates the Effective Population Size (loosely, the number of breeding individuals contributing to genetic diversity) of wolverines across the U.S. Northern Rockies (ID, MT, WY) and North Cascades (WA) to be only around 35 animals. Even in the largest of Idaho’s mountain ranges, numbers of wolverines only exist in single digits. This is particularly concerning, given their extremely low reproductive rates. In these subpopulations, the non-target take of even a single breeding adult could be devastating. They don’t breed until they reach 3-4 years of age and, depending on nutritional health, don’t produce young every year. Mortality rates for the one or two kits that make up a litter average around 50%. Once the female finishes nursing, she’ll bring meat to her kits, as they don’t yet know how to find it. Often this happens during the peak of the wolf trapping season. Encountering a trap at this time would be dire—not just for her, but for her dependent kits. Because of their family structure, the loss of a mature male could be even more consequential. As one renowned retired U.S. Forest Service wolverine researcher, Jeff Copeland, put it, “you really can’t afford ANY incidental mortality in these isolated subpopulations.” Despite this, in the last two years alone, two incidental trapping events took place in Custer County (think Sawtooths)—one resulting in death.

Incidental captures of wolverines through actions of recreational trapping clearly constitute a “take” as defined by the ESA and exceptions for this activity are not appropriate based on the highly vulnerable status of the species.

ICL is grateful that the USFWS has listed wolverines under the ESA. After decades of legal ping-pong, the single biggest decision to potentially reverse the precarious status of the animals has finally been made. Now, the agency needs to begin setting up conservation measures for the species’ protection and ask for changes to the actions we know affect wolverine survival. To every degree possible, the USFWS recovery planning process must minimize all human caused impacts to wolverines. We believe that allowing incidental take from trapping activities the USFWS does not meet this threshold. There’s no such thing as an “incidental” wolverine.

The USFWS is accepting public comments on the 4(d) rule through January 26, 2024. Please tell the USFWS that they should reconsider their 4(d) exceptions allowing Idaho to cause harm to wolverine populations.  Take this action for wolverine at the button below!


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