The Predator/Prey Domino Effect

When trappers and hunters choose to decrease their fur harvesting efforts, the impact on prey species and livestock is predictable and often devastating.

The Predator/Prey Domino Effect

In classic domino fashion, harvesting coyotes, foxes and bobcats keeps these predator populations reduced and benefits wildlife and domestic livestock.

I remember as a kid lining up a rows of dominos over and over just to watch them fall, in predictable fashion, as each tumbling piece affected the momentum and direction of the next. This domino effect — or chain reaction — I learned later in life is the cumulative result of one event setting off a succession of other related events. I also learned that similar chain reactions occur in nature both randomly and by design and are neither inherently good nor bad — they simply exist. Predator/prey relationships are a fundamental example — a classic case being the symbiotic relationship between the snowshoe hare and Canada lynx. Lynx numbers rise and fall with cyclic fluctuations in snowshoe hare populations. When hares are abundant, lynx populations expand. But when hare numbers crash, lynx must seek alternative food sources, and ultimately their numbers decline.

Nature is full of similar checks and balances designed to establish equilibrium in habitats occupied by various species of plants and animals. And each has a carrying capacity based on the amount and quality of the resources within. Predator/prey relationships — such as the lynx and the hare and others — provide one balancing mechanism. Prey species by design produce surplus populations, and if left unchecked can have a ruinous effect on the habitats they occupy. Predators help keep these animals in balance with the habitat. In turn, the abundance or lack of prey determines the health and well being of predator populations. As prey populations ebb and flow, they cause chain reactions — a domino effect — that can have a far reaching impact on predatory species and the habitat in which they live.

It shouldn’t come as a surprise that the human component — trappers and fur hunters — also can affect the predator/prey balance by how aggressively they harvest furbearing predators, which is often determined by the monetary value of their pelts. In classic domino fashion, harvesting coyotes, foxes and bobcats keeps these predator populations reduced. But when the fur harvest is decreased, most often due to a decline in fur value, predator populations explode and can have a devastating impact on waterfowl and upland game bird nesting success in the Dakotas, pronghorn fawn recruitment in the Southeast and domestic livestock in America’s heartland. 

Mike Wilhite, editor and fur market analyst for Trapper’s Post magazine says that fur prices definitely have an impact on furbearer populations. “Many won’t trap during low price years so furbearer numbers climb,” he said. “And when predator populations exceed the carrying capacity of the land, game populations suffer and [the predators] move on to livestock and domestic pets. Obviously, as a trapper I’m going to hit the trapline harder when fur prices are higher. Being a multi-species trapper helps because I can concentrate efforts on those furbearers that’ll make me some money while letting the others slide for a season.”

When trappers and fur hunters choose to pull back their efforts, the impact is predictable and often devastating. The following studies, while somewhat dated, occurred when commercial trapping was reduced due to low fur prices which caused a spike in predator numbers. They provide supportive data that persistent predator control can have a positive effect on prey species and livestock survival and recruitment dynamics.

Unchecked predator populations in the prairie pothole regions of the Dakotas can have a negative effect on waterfowl recruitment as they target nesting hen ducks.
Unchecked predator populations in the prairie pothole regions of the Dakotas can have a negative effect on waterfowl recruitment as they target nesting hen ducks.

Example: A study conducted by Delta Waterfowl in North Dakota, examined the effects that predator removal — foxes, skunks and raccoons — had on duck nesting success in areas with marginal grasslands. The project was initiated in the mid-1990s and continued until 2008. According to Joel Brice with Delta Waterfowl, removing the predators from these areas consistently doubled and tripled nesting success compared to blocks of similar land where there was no trapping of these furbearers. Nesting success averaged 70 percent success where predators were trapped, but only 39 percent where no predator control was exercised. In the Nickolaisen Waterfowl Production Area near Cando, North Dakota, predator removal resulted in duck nesting success approaching 80 percent — far above the 15 to 20 percent benchmark needed to sustain duck populations. 

Example: The Arizona Game and Fish Department has used lethal methods — ground and aerial shooting — to remove coyotes from Game Management Units where pronghorn fawn mortality rates have been exceedingly high. According to Regional Supervisor Raul Vega of Arizona Game and Fish in Tucson, the department’s intent was to give newborn fawns a chance to survive long enough so they can effectively escape the predators. 

Vega told Arizona Range News that, “Research has clearly and repeatedly shown that coyote-caused fawn predation can be a significant limiting factor affecting pronghorn fawn survival and recruitment rates. It is particularly devastating to populations facing other habitat-related challenges, such as long-term drought.” When compared to the five-year average, the fawn-to-doe ratio in the areas where coyotes were aggressively hunted nearly doubled soon after the removal efforts were initiated. 

Example: But perhaps even more telling is the effect that rampant coyote populations have on domestic livestock. In 1989, the U.S. Government Accountability Office estimated that coyotes in the 17 Western states killed sheep and lambs valued at $18. The National Agricultural Statistical Service (NASS 1991) reported that sheep and lamb losses to coyotes in the United States were valued at $18.3 million in 1990. Former sheep producers reported that one of the principal reasons for leaving the sheep industry included high predation losses.

OK, here’s where it gets interesting. A study conducted by the American Sheep Industry Association, showed a positive correlation between the price paid for a coyote pelt and the number of coyotes harvested that year. In 1982, (five years before the fur market crashed in 1987) coyote pelts brought an average price of $34.92, and 421,000 coyotes were harvested by private fur hunters and trappers. However, a decade later, when the average price paid for coyote pelts had dropped to $13.53, the annual harvest decreased to 158,000. That’s a 63 percent decrease in 10 years. As the value of fur pelts plummeted, so did hunters’ and trappers’ motivation to pursue them. 

Sheep and lamb losses in states where annual data were available increased from 6.9 percent of the stock sheep and new-crop lambs inventory in 1983, to 11.7 percent of the same inventory in 1994, a 70 percent increase. Again, these are pre- and post-market crash data. 

Same thing with domestic goats. In three studies in Texas prior to the fur market crash (1985), where an estimated 1.1 million goats (about 90 percent of the goats in the United States) are raised, predators were reported to take 18.1 percent of the adults and 33.9 percent of the kids. NASS reported that goat losses to coyotes in the United States were valued at $5.7 million in 1990.

Cattle? Yep. According to data released in 2011 by the National Agricultural Statistics Service (NASS), cattle and calf losses from animal predators totaled nearly 220 thousand head during 2010. This represented 5.5 percent of the total deaths from all causes and resulted in a loss of $98.5 million to farmers and ranchers. Coyotes and dogs caused the majority of cattle and calf predator losses accounting for 53.1 percent and 9.9 percent respectively.

So the data supports the premise that trappers and fur hunters can cause a chain reaction by choosing not to harvest furbearing predators — precipitated by a decline in fur value and other economic factors. “The value of the U.S. dollar vs. foreign currencies, politics, fashion trends and the weather all play a part in the fur market,” said Wilhite, “and this all determines just how aggressively trappers and fur hunters pursue furbearers.” Add to that the COVID 19 pandemic, which as caused fur harvesting efforts to be further hampered as international and local fur auctions were suspended in 2020, creating a surplus of fur with no marketing outlet to speak of.

Coyote hunters benefit no matter which way fur prices trend. When they are high, they enjoy a better return for their harvest. When they are low, trapping efforts decrease and hunting opportunities soar.
Coyote hunters benefit no matter which way fur prices trend. When they are high, they enjoy a better return for their harvest. When they are low, trapping efforts decrease and hunting opportunities soar.

When predator populations are left unchecked, they can have a devastating effect on game and non-game prey species and domestic livestock. And diseases such as mange, parvo, distemper and others become rampant as coyotes, foxes, raccoons and other furbearing predators exceed the carrying capacity of their habitats — Mother’s Nature’s solution for overpopulation. Only when coyotes and other predators are aggressively trapped and hunted — and in some cases, animal damage control measures taken — is the balancing act between predators, prey and habitat optimal.

But no matter in which direction the dominos topple, there’s good news for fur hunters. When fur prices are high, they enjoy a higher return on their harvest. When fur prices are low, and trappers take their collective foot off the gas pedal, predator numbers are high and hunting opportunities soar. So maybe it’s time for fur hunters to help initiate a domino effect that will reduce predator numbers and create balanced, vibrant predator/prey communities — by getting out and hunting fur more aggressively.

As an Amazon Associate we earn from qualifying purchases.


Discussion

Comments on this site are submitted by users and are not endorsed by nor do they reflect the views or opinions of COLE Publishing, Inc. Comments are moderated before being posted.