In 1971, wild horses and burros were found roaming across 53.8 million acres of Herd Areas (HAs), of which 42.4 million acres were under the Bureau of Land Management's (BLM's) jurisdiction. Today the BLM manages wild horses and burros in subsets of these HAs, known as Herd Management Areas (HMAs) that comprise 31.6 millionacres, of which 26.9 million acres are under BLM management.
The Havasu HMA lies in west central Arizona along the Colorado and Bill Williams rivers. The HMA is split into two units by the Colorado River. The Havasu HMA is also adjacent to the Chemeheuvi HMA on the California side.
The Havasu HMA consists of 450,790 acres of Lower Colorado Sonoran Desert. The Arizona side of the HMA is 372,568 acres, while the California side of the HMA encompasses 78,222. The wild burros of the Havasu HMA roam freely throughout the area, which is characterized by arroyo-scarred alluvial fans to steep and rocky volcanic mountains. There are four major vegetation community typesfound within the HMA. These include open hills characterized by creosote bush, primary and secondary wash characterized by palo verde and burro bush, and secondary wash of predominately palo verde andcreosote.
Summer temperatures can exceed 125 degrees, with about 100 days per year of above 100 degree temperatures. Wild burros share this habitat with desert bighorn sheep and desert mule deer. Other animals in the area include small mammals, desert tortoises, several species of rattle snakes, a variety of birds, including the southwestern willow flycatcher, lizards and amphibians.
Burros began to populate the area along the lower Colorado River after a short-lived mining boom in1858. With the decline of mining and the emergence of the railroad at the end of the nineteenth century, many of the animals were abandoned into the surrounding hills.
Burros evolved in the harsh deserts of North Africa and adapted very well to the Havasu HMA's desert environment. Left alone in this remote region with few natural predators, the wild burro population thrived. Today, the population of burros is estimated to be about 540 animals (240 in Arizona and 300 in California). In this area, about 90 percent of the burros are gray in color, with the remaining 10 percent being black, brown, white, pinto or piebald. Some burros possess the shoulder cross characteristic of the ancestral Nubian wild ass and many have leg barrings associated with the Somali wild ass. Adult burros average 48 inches in height and weigh about 350 pounds. In the summer months, the burros concentrate in the critical area, which is generally within one and a half miles of all major water sources. During cooler months, the wild burros normally move into the mountains and scatter throughout the area.
The wild burros of Havasu HMA are managed in an ecological balance within their habitat to protect the forage plants. This ensures that there is plenty of feed for the burros, as well as for the other wildlife species. When the vegetative monitoring sites show that the wild burro population exceeds the Appropriate Management Level, which is currently 320 wild burros (170 in Arizona and 150 in California), the Bureau of Land Management will remove some of the animals and offer them to the public through BLM's Adopt a Wild Horse or Burro Program.
For more information, contact the Lake Havasu Field Office at 2610 Sweetwater Ave, Lake Havasu City, Arizona, 86406