Futility of Trapping as Wildlife Management Tool
Despite a 25 year effort to reduce coyote populations through trapping, Maine’s coyote population has remained the same since 1985. In fact, over the entire continent, coyote populations are at an all time high despite many generations of trapping. Coyote litters vary between 1 and 19 pups. Trapped populations increase reproductive rates (frequency of litters and the number of pups in a litter) drastically to compensate for mortality. Due to this compensatory breeding, it has been shown that trapping actually leads to higher coyote populations in the long term. Where coyotes are not trapped (e.g., some National Parks), their populations densities tend to be lower than in areas where trapping occurs.
In the short term, coyote trapping can cause another problem. If coyotes are removed, mesopredator populations (smaller predators like raccoon and skunk) often grow overabundant and lead to management problems (e.g., damage to native ground-nesting bird populations, conflicts with human use, disease, etc.), which, in turn, are cited by trappers to justify even more trapping. On public lands, wildlife is better left to self regulate, unless authorities have to surgically target a local problem due to concerns for public safety or a threatened species.
Wolf management is another example of the futility of trapping. Trapping was recently re-instituted as part of a management regime in Montana. In areas near Yellowstone National Park most wolf packs had established a firm territory and had an adequate prey base. They were less likely to depredate on livestock than packs in other areas of Montana, because they had less reason to disperse or seek new food sources. Instead of focusing their efforts on problem animals and areas where conflicts are more likely, recreational trappers conveniently targeted the Yellowstone area and killed many of the alpha individuals and all of the GPS-collared wolves. As a result, without the older, dominant animals, the subdominant and younger wolves will likely compete in a struggle for a new hierarchy, will breed more (typically only alpha individuals breed), and conflicts will push younger, inexperienced animals from their established territories. These will disperse into areas where human-wolf conflicts will rise. Thus, by destabilizing pack structures, trapping may do more harm than good. Moreover, without GPS-collared animals, scientists will be less well positioned to predict potential conflicts and mitigate them.
RTPL is similarly impractical in pest management. In Washington State, wildlife authorities have tried to use private recreational trapping to control nutria, an introduced exotic species, but nutria pelt prices are so low that trappers do not care to trap them. Instead, they target the native species whose populations are smaller and whose pelt prices are accordingly higher.
The most commonly trapped “pest” species is the beaver. Beaver populations self regulate. After colonizing a new area, populations grow quickly, but they subsequently drop to about 25% of the peak population. Trapped colonies show a higher reproductive rate, so they often end up being larger than self-regulating colonies in the long run, unless trapping is continuous and pervasive, which is always costly (both financially and in terms of unintended consequences).
Most importantly, beaver provide vital services in an arid state like Montana. It makes a lot more sense to employ beaver deceivers (non-lethal devices that prevent beaver from damming sites like culverts), to relocate beaver, or to find other creative ways to coexist with them, because they provide valuable services: water quality and availability for fish, for livestock, for fire suppression, riparian habitat for birds, waterfowl and ungulates, etc.
Lastly, beaver and other “pests” are generally a private lands issue. Therefore, recreational trapping on public lands cannot address these issues effectively. A block management model, private landowner solutions or trained authorities are more suited to resolving these problems.
Private trappers have no incentive to trap diseased populations (their incentive is pelt prices, and pelts of diseased animals are rarely worth anything), and even if they did, traps cannot discriminate between diseased and healthy individuals. Invariably, more healthy animals are caught. In fact, trapping has occasionally made disease problems worse by increasing dispersal rates. Brian Giddings, director of the Montana FWP trapping program, has said: “Neither FWP nor I have made claims that there is scientific information that addresses the relationship between recreational trapper harvest and disease control…..FWP regulates furbearer trapping seasons for recreational harvest opportunities. Montana’s harvest seasons are not based on reducing or controlling diseases.”