Surviving The Purge: How Coyotes Respond to Predator Control
By: Dean Taylor
With fall approaching and big game hunting back in the sights of hunters all over the country, the subject of predator control will undoubtedly reignite as empty-handed hunters exit the woods to the familiar song of wolf and coyote howls. While predator control has long been part of wildlife management in North America, and has arguably become necessary in some parts of the country, experts such as Dan Flores, in his book Coyote America, suggest that in the case of Coyotes, our large-scale predator control methods may be having the reverse effect and that perhaps the near-century long war with coyotes should come to an end.
A Brief History of Predator Control
Although the attitudes today around coyotes may still not be overwhelmingly positive, their bad reputation was perhaps at its height between the 1860s and the 1930s.
For the period leading up to the 1860s, Coyotes were primarily hunted for their pelts alongside other western game such as Wolves, Mountain Lions, and the iconic Buffalo. As settlers continued to head west and the fur trade continued to pick up steam, the market hunting of these animals became extremely lucrative with a Coyote fur even being accepted as currency in some parts of the American West.
With Buffalo numbers dwindling to near extinction, predators such as Wolves and Coyotes began to take centre stage around the 1860s when pressure from Stockmen’s Associations led to large bounties being placed on these animals to rid the west of its cattle-killing predators. This bounty put a much higher price on predators than ever before, leading many fur traders and market hunters to seek out more efficient ways of hunting these often elusive animals. The hunt for a more effective killing tactic led quickly to poisons, introducing Strychnine into the predator hunting world for the first time.
Strychnine, made from the seeds of an East-Indian tree, is a highly toxic substance that was being developed in the United States as early as 1834. This substance is a highly effective pesticide, killing the animal rather gruesomely by causing intense full-body muscle cramping until an eventual death by suffocation. Deadly in very small doses, this poison was able to be distributed in very small and discrete tablets, allowing it to be hidden in the predators' natural food sources without tipping off surrounding animals to the cause of death.
Being unregulated and highly affordable at the time, many fur traders and market hunters began carrying tablets of the substance on their hunts, lacing the carcasses of animals they killed with the poison in hopes of killing the predators as they scavenged the site. This tactic proved to be highly effective, allowing hunters to collect dozens of poisoned Wolves and Coyotes for days after their kill and capitalize on the newly set bounty.
While market hunting was deadly in and of itself, the real "War on Wild Things”, as Flores calls it, began in the early 1900s when the government began getting in on the action. Government-funded predator control was first seen in the State of Montana, when in 1905 the state's legislature passed a law requiring veterinarians to introduce Sarcoptic Mange into local wild canine populations, an event that's remnants can still be seen to this day in modern wolf and coyote populations as far north as Alberta. During this same year, predator control was also picking up steam on the federal level when the United States Department of Agriculture's (USDA) Division of Biological Survey switched its focus from wildlife surveys to the elimination of wolves and coyotes.
This change in focus was primarily attributed to the relatively newly established national forests in the State of Montana, specifically Yellowstone and later Glacier, which were being blamed for harbouring large numbers of cattle-eating predators such as wolves, mountain lions, and coyotes. The pressure from the highly influential Stockmen’s Associations resulted in congress giving the Biological Survey the go-ahead to rid the national forests of its predators in 1914. By 1920, the survey had succeeded in ridding the area of its most dominant predator, with wolves being virtually extinct in the area due to extensive poisoning and denning efforts. While these efforts were highly successful in ridding the area of its wolves, one glaring and mysterious problem still loomed over the project: coyote numbers were still on the rise.
How Coyotes Respond to Predator Control
With coyotes remarkably surviving a government-funded purge on wild canids, researchers began to take notice of the extraordinary adaptability of wild coyotes in the face of a program that was able to virtually wipe out its close cousin, the American Gray Wolf. The example in Montana is just one of many resilience stories for these animals, however, it helped exemplify the ways in which they respond to stress on their population compared to that of wolves.
One of the unique ways that Coyotes adapt to stress on their population is in their ability to vary their litter sizes. Coyote populations under regular amounts of stress, for example, will often see its females breed litters of around 5-6 pups. When these same populations are under stress, however, such as from large predator control efforts, these litters can be as large as 19, causing populations to actually grow rather than reduce during population control efforts.
This ability to adjust litter sizes comes from their assessment of the amount of prey that is in the area. When populations are stable, for example, Coyotes produce small litters to avoid overpopulation and over-saturating their landscape. When prey is abundant, however, such as when wolves or other coyotes are eliminated, litter sizes respond accordingly and produce more pups due to the large availability of food (Gese, 2005).
In addition to these larger litters, the age in which females reach reproductive maturity also appears to be sped up by population control efforts. Coyote packs under normal circumstances, as Flores points out, typically consist of a breeding alpha pair, accompanied by one and two-year-old female pups from previous litters. However, when these pairs are disrupted and alpha females are removed from the population, these young females begin to take their place, reproducing at a much earlier age than they otherwise would have. This ultimately leads to more females breeding and a much higher survival percentage of pups.
In addition to their population growing in the areas they currently occupy, Coyotes also quickly fill the gaps left by the absence of other predators, expanding their home ranges from their western origins to their modern grounds as north as the Yukon, as east as Newfoundland, and as urban as Downtown Chicago.
Coyote walking down an empty street in Downtown Chicago
Conclusion
While I am by no means against predator control when sensitive game populations are threatened and the methods of doing so are humane, the data surrounding the resiliency of coyotes seems to suggest that efforts in killing coyotes are ultimately wasted. Despite the evidence of the program's deficiencies, the Wildlife Services in the US still kills around 80,000 coyotes per year in the name of predator control, with strychnine being used as a method of take in both the US and Canada (Weber, 2020). Due to both the dangers of strychnine to untargeted species and the mounting evidence that the large-scale population control of coyotes is having the reverse effect on the animal’s populations, it is perhaps time that the government abandons this project and leaves the job of predator to control to trappers and landowners.
Sources:
The majority of the information from this article was summarized from Dan Flores’ Coyote America, specifically the chapter “The War On Wild Things”. The book can be found at the link above and is an excellent read for anyone interested in the history of coyotes and how they have adapted to a century long purge on their populations.
Flores, D., 2017. Coyote America. New York: Basic Books.
Supporting information was taken from:
Gese, E. (2005). Demographic and spatial responses of coyotes to changes in food and exploitation.
Weber, B., 2020. Environmental Groups Ask Why Strychnine Banned Against Gophers But Not For Killing Wolves. [online] The Globe and Mail. Available at: <https://www.theglobeandmail.com/canada/alberta/article-environmental-groups-ask-why-strychnine-banned-against-gophers-but-not/> [Accessed 1 September 2020].