Resource Management

The refuge’s primary management goals are focused on the recovery of the Sonoran pronghorn.

For thousands of years, Sonoran pronghorn migrated seasonally within the vast Sonora desert – from southwest Arizona and California down into the northern portion of Sonora, Mexico. If they found themselves in an area affected by drought conditions, the well-adapted pronghorn would travel long distances to find food and water sources elsewhere.

With human settlement, the ability of the pronghorn to move within its historic range diminished considerably. Extreme drought conditions, loss of grazing areas to cattle, agriculture, and urbanization impacted the pronghorn’s habitat. Not only did they lose habitat, roads, fences, and irrigation canals and other structures restricted their movement. The migratory herds were not able to shift with the changing conditions as they had historically. By the early 1940s, the remaining population occupied only eight percent of its historical range. By then, only around 600 animals in Sonora, Mexico, and 80 animals within southwestern Arizona existed. Then the Southwest’s driest year on record occurred in 2002 and the already-declining population in the United States dwindled to an estimated population of 21.

In an effort to prevent the extinction of the species, the U.S. Fish and Wildlife Service (Service) and its partners began a captive breeding program in 2003. Working with other agencies and Mexico, the Service captured seven pronghorn to start the captive-breeding program. A square mile of desert was set aside on Cabeza Prieta National Wildlife Refuge to hold the captive animals. Within the enclosure, water guzzlers and supplemental food were provided. The pronghorn were protected from predators like coyote and mountain lions, and these pronghorn successfully reproduced.

Within the enclosure, the captive population grew and in 2006 the refuge began releasing some of the young males. The captive-reared animals were able to integrate well with the wild population. To date, 91 pronghorns of both sexes have been released into the wild and as of December, 2012, the overall wild population of Sonoran pronghorn is estimated to be at 160 animals – and growing.

While the captive breeding program offers real hope, the Service is taking additional steps to ensure the recovery of the pronghorn. The Cabeza Prieta National Wildlife Refuge has installed water sources and foraging plots for the pronghorn and other wildlife. Artificial catchments and water guzzlers throughout the refuge provide a critical source of water for wildlife. Cabeza Prieta Refuge began putting in water-catchment systems as early as the 1940s for desert bighorn sheep when the refuge was a “game range.”  Early designs were often created by enhancing naturally occurring tenajas (a rock or geologic formation that naturally retains water and acts as a cistern), creating artificial tenajas or building small dams and storage facilities to capture and store runoff from small canyons. It was not until 2003 that water development was constructed specifically for the recovery of Sonoran pronghorn. Today, rainwater is captured in washes or from sheet flow and diverted to underground storage tanks, where it is then gravity-fed through pipes to a ground-level trough. The largest of these systems stores 18,000 gallons, providing a stable water supply for potentially more than one year.

Along with the water catchments, the refuge and its recovery partners have created five separate forage plots ranging between five to ten square acres in size. Much like the irrigation systems commonly used in agriculture, they include wells with pumps and generators and above-ground piping to ensure the areas pronghorn prefer to forage in during the summer months have green vegetation available during dry periods.