Wild Burros Collide With the Ranching and Farming Economy

By Marina DeWit – Region 9 Advocate 

Hiking in the mountains and rugged terrain is a popular tourist activity in Arizona.  When exploring areas around lakes and rivers, the chances of meeting wildlife are pretty high at any time of the day, year round.  In the northwest valley of the greater Phoenix region, the most common encounter is with one of the many herds of wild burros who roam the land around Lake Pleasant.  As exciting as it may be for a family on a hike to see wild burros close to the road, and their adorable babies in the spring time, these animals are not a welcome sight to the cattle ranchers and farmers who raise livestock and grow produce nearby. 

Many ranchers refer to burros as an invasive species that are destroying their businesses.  Besides trampling the ground and reducing vegetation on the range, the burros are territorial animals that break ranch fences, invade farmland, and at times injure and release livestock.  Overpopulation of these large burros in one area leads to overgrazing, starvation, thirst, loss of native vegetation, and the spread of invasive weeds.  Burros may also venture on to highways and private property in search of food and water.  Since killing burros is a crime under the Wild-Free Roaming Horses and Burros Act and the Bureau of Land Management (BLM) is not efficiently controlling the number of animals on public lands, ranchers and farmers in the area feel helpless and are struggling to maintain their livelihood.   

Wild burros and horses are not native species, they are descendants of animals brought to the Americas in the 1500s by the Spanish explorers.  They are feral animals that adapted to the Western range and compete with domestic cattle and sheep for resources.  In the mid-1950s their numbers were in drastic decline due to hunting and slaughter to meet the demands of the pet food market and to open up grazing land for livestock.  In 1971 Congress passed the Wild-Free Roaming Horses and Burros Act that covers the management, protection and study of “unbranded and unclaimed horses and burros on public lands in the United States.”  

The Act directs the BLM to determine the appropriate management level (AML), that is, the number of wild horses and burros that can thrive in balance with other public land resources.  The animals in excess of the AML are to be removed from the range and put into adoption or sales programs.  After receiving federal protection, the wild horse and burro population soared.  It is a federal crime for anyone to harass or kill these animals, and without natural predators, the herds can double in size in just four years.  In March 2019, the wild horse and burro population on public lands was estimated at over 87,000, more than three times the nationwide AML of 26,690.  The BLM programs have not kept up with population growth, and according to the agency, nearly two-thirds of program budgets go to care for unadopted and unsold animals, leaving few funds for on-range management and care.   

Burros crossing the road in the Lake Pleasant area in Peoria, AZ.

Wild burro populations in Arizona far exceed local AMLs.  In the Lake Pleasant Herd Management Area, the AML for wild burros is 208, but the 2015 estimated population almost two and a half times that, at 552.  Just northwest of Lake Pleasant, in the Big Sandy Herd Management Area, the AML is 139, but the wild burros number 1,201, almost nine times more! 

The process for removing excess animals from the land is very lengthy, and the numbers of animals multiply in the meantime.  When a rancher files a complaint with the BLM about excess burros, an environmental assessment takes place, comparing the herd population size and vegetation data.  After the public comment period ends (about 30 days), the BLM decision on the action to take is put out for the public to see again.  A significant amount of time may pass while results are being analyzed and an action plan put in place.  Once an animal collection is approved, contractors have to be engaged to gather them via helicopters, trucks, or horseback.  The process of seeking approval to remove burros may take a year, during which time the herd size may increase by 15% to 20%.  Yet, any extra animals are not getting factored into the formula, leading to a permanent imbalance.   

Wild burros have been expanding their range year by year, overlapping with urban areas.  The number of collisions between burros and vehicles has increased in many parts of Arizona, posing a growing risk to public safety and animal welfare.  The U.S. Geological Survey, BLM, and Arizona Game and Fish Department are studying the potential of fertility control drugs to reduce foaling rates.  The study may take three to five years to complete but will improve the understanding of burro movement and demographics (e.g., birth rate, herd health, natural mortality rate).  Currently, the only available fertility control vaccine, porcine zona pellucida (PZP), is effective for just one year and must be hand-injected into a captured animal.  Another formulation of PZP can be deployed via darting, but it is difficult and expensive to locate and track individual animals.   

Legislative actions to reduce the impact on small businesses have been proposed, but the sides disagree on the solutions.  Farmers and ranchers want the burro population in the BLM areas reduced and are willing to look at all options.  The BLM has acknowledged that capturing, training, and lodging can cost $50,000 per animal, so it recognizes the need to find new ways to manage wild burros that benefit the animals, the land and U.S. taxpayers.  Farmers and ranchers are hopeful that whatever solution legislators can agree on is enacted soon, as the economic drain on their family-run enterprises grows each year. 


Marina DeWit serves as the Region 9 Advocate for the SBA Office of Advocacy, representing small businesses in Arizona, California, Nevada, Hawaii, and the Pacific Islands of Guam, American Samoa, Commonwealth of the Northern Mariana Islands, and Trust Territories. DeWit works with small business owners, state and local governments, and small business associations to bring the voice of Region 9 to Washington DC. She can be reached at Marina.DeWit@sba.gov.

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