Competition in the Desert

It doesn’t take much time to spot a feral horse in the desert in southwest Wyoming. Within 10 minutes of the town of Green River, along the well-traveled Wild Horse Loop, onlookers can take in a dozen with ease. Drive a little farther down the rocky, slate roads and one can see 25 in an afternoon. Sometimes the horses cluster along the horizon line, easily spotted without binoculars. The free-roaming equines are much larger than elk and at least triple the size of the biggest buck pronghorn. More often than in years past, you can find them nearer to the road — a photographer's easy snapshot out of a vehicle window. 

Horses often pass their time idling and grazing, seeming docile and non-intrusive. But their swelling presence and newly-exerted dominance is startling. In recent years the Wyoming Game and Fish Department has become increasingly aware of the high — and rising — number of feral horses in Wyoming and their negative impacts to wildlife habitat. “We are concerned about horse numbers as they exceed the appropriate management level for each herd,” said Doug Brimeyer, Game and Fish deputy chief of wildlife. “We’ve seen how the overpopulation of feral horses have impacted important wildlife habitat in neighboring states like Nevada and Utah, and we want to prevent that from happening in Wyoming.”

While many people consider these horses as living symbols of the historic and pioneer spirit of the West, few understand how feral horses have become vastly overpopulated in the western states, including Wyoming. As that number increases, so does the severity of looming impacts on the health of the state’s rangelands and the competition for limited water resources in the desert — a situation that is not good for wildlife or feral horses.



Feral horses in Wyoming are not native. Literature notes true wild horses went extinct in North America between 10,000 to 12,000 years ago and were never domesticated. The horses free-roaming the western landscape lineage traces back to domestic stock introduced by Spanish explorers in the 16th and 17th centuries. Thus, the moniker “wild” doesn’t truly describe the horses on the landscape now. Today’s population of free-ranging horses were established by European explorers, augmented by early settlers and managed for human use, not as a reintroduction of a native animal. The accidental — and intentional — release of domestic horses changed free-roaming horse populations and genetics, stemming from westward human expansion and the development of Wyoming’s agricultural industry. Some livestock producers used feral horse herds as brood stock and would sometimes release stallions to intentionally alter feral horse genetics for their purposes. During the early part of the 20th century, through World War II, ranchers even gathered, raised and trained feral horses for ranching needs and to outfit the U.S. military. 



By the early 1970s enough horses roamed freely that their population had to be curtailed. The Wild Free-Roaming Horses and Burros Act of 1971 directed the Bureau of Land Management to determine the areas in the West where horses were found roaming. Those areas were identified as herd areas. Each herd area was evaluated to determine if all — or a portion — of that area could be managed for horses based on a variety of factors, including conflicts with private land or other resource values such as wildlife habitat.  Areas that could be managed for horses were identified as herd management areas; however, some BLM lands where horses were found in 1971 are not currently managed for feral horses. The BLM is required to determine the appropriate management level for each herd management area, which reflects the number of horses allowable when considering ecological factors and other values, including wildlife, livestock grazing, recreation and conflicts with private land. Further, the BLM is required to manage herd management areas in a manner that maintains a “thriving natural ecological balance.” 

In present-day, the BLM manages 16 herd management areas on nearly 5 million acres in Wyoming. Although the BLM has conducted removals in the past, at least seven of the herd management areas in Wyoming have horse numbers in excess of established and appropriate management levels. The combined appropriate management level for all herd management areas in Wyoming is 3,795 horses. However, as of fall 2021 prior to any round-ups, there were at least 8,700 horses in Wyoming; more than twice the number determined to be appropriate for these areas.



Food and water lie at the crux of the competition between feral horses and wildlife. “There is a concern that in an arid environment, in the high-elevation desert, there will be a competition for resources — primarily water,” said Todd Graham, Game and Fish wildlife supervisor in the Green River Region. Horses can cause additional stress on wildlife through competition for water. Recent studies on wildlife-horse interactions documented horses keeping elk from water in Colorado. In Nevada, horses have been noted displacing pronghorn from water, and completely degrading natural springs where wildlife drink. Throughout the West, pronghorn and mule deer have been documented using water sources less often where horse activity was high. 

In Wyoming, biologists and hunters have started to see similar issues with feral horses keeping elk, deer and pronghorn from using limited water sources. “There is a bully factor at waterholes,” said Kim Olson, game warden in Baggs on observing horses in her district. “As water becomes more scarce, there will likely be more conflicts where feral horses will keep other animals from getting a drink.”

Habitat conditions are also a concern. Feral horse populations that exceed appropriate management levels alter rangeland vegetation and soils, which can negatively impact wildlife habitat. Recent research has focused on the negative effects to sagebrush, which directly affect sagebrush obligate species. This is especially concerning in arid landscapes such as southwestern Wyoming. Wyoming wildlife managers hope to stave off impacts through habitat restoration, and some fencing projects in the Green River area have made attempts to protect crucial water sources. “We’re looking at more habitat and water projects, especially to be proactive in places where feral horse numbers are particularly high,” Brimeyer said.



The biggest factor to the competition between wildlife and feral horses is simple: there are too many horses. As feral horse numbers continue to increase, habitat degradation and subsequent impacts are inevitable in Wyoming. Overpopulation of feral horses could eventually lead to high horse mortality rates in areas where resources can no longer support these populations and limit the growth of wildlife populations. Without a significant increase in the rate of removal of feral horses, their growth and population expansion is inevitable. Feral horses can live up to 30 years. Unmanaged populations can double in size every four to five years due to a lack of natural predators and a rapid growth rate. In Wyoming, horses have expanded outside of established herd management area boundaries, creating conflicts with other landowners, including conflicts on privately-owned lands. This ignores the provisions of the Horses and Burros Act that requires maintaining horses on BLM-administered land, within established herd management areas and removal of feral horses from privately owned land. Feral horse populations and conflicts on private lands continue to be a major problem in Wyoming.

According to the Horses and Burros Act, horses in excess of the established appropriate management level must be removed from the land. Several horse management practices have been used since Congress passed the act. Management practices outlined in the act include: population counts and habitat assessments to determine where overpopulation exists; roundups to remove animals; use of contraception to reduce productivity; adoption of horses to private owners; and euthanasia of old, ailing and unadoptable animals. Management involving euthanasia, and sometimes roundups, often face legal challenges and are severely restricted by public opinion. However, while the public and interest groups express concerns about the removal of horses, there is seldom discussion about the likelihood that horses can die from starvation, lack of water and exposure when their numbers exceed the carrying capacity of the area. And, there is even less public attention to the ways horses and wildlife compete for the same limited resources.



The literature on unmanaged feral horse grazing shows feral horses can have substantial negative impacts on native wildlife populations and rangeland health. More attention should be given to the management of feral horses in Wyoming and the legal mandates that require an appropriate number of feral horses on the state’s rangelands. “We feel strongly that feral horses need to be managed and managed to levels prescribed in management plans that were developed through biological and habitat capacity analyses,” Brimeyer said.  Attempts for the BLM to make steps toward managing populations are continually roadblocked, both financially and logistically. How to manage horses is a contentious topic, with pressure from special interest groups with extremely divergent opinions. Even with additional funding, more aggressive management actions — such as major removals — are continually challenged by public opinion and lawsuits. 

Game and Fish remains committed to supporting reduction efforts and encouraging the BLM to direct more resources towards removing enough feral horses each year to conserve the desert habitat in southwest Wyoming. As the 2021 fall/winter round-up proceeds, Game and Fish is encouraged by the progress BLM has made to reach the goal of gathering 4,300 feral horses from Wyoming. Applying appropriate management actions is an issue that broad stakeholder groups — feral horse advocates, wildlife advocates and ranchers — should support to ensure healthy rangelands for feral horses, wildlife and livestock. 

— John Kennedy is the deputy director of internal operations for the Wyoming Game and Fish Department.
Photographer Info
Greg Berquist

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