In June 2012, the Bureau of Land Management (BLM), Yuma, Arizona office, gathered 350 feral burros on private, state, military, BLM and National Wildlife Refuge lands along the lower Colorado River in the southwestern corner Arizona. The gather was funded by the U.S. Army Garrison – Yuma due to an overabundance of burros and safety concerns.
The Cibola-Trigo Herd Management Area, encompassing ~832,000 acres, located in southwestern Arizona and extreme southeastern California, supports populations of wild horses and burros that use lands administered by the U.S. Army Garrison, Yuma Proving Ground, U.S. Fish and Wildlife Service (Imperial and Cibola National Wildlife Refuges), and the BLM. BLM is responsible for managing the herd according to the Wild and Free-Roaming Horse and Burro Act of 1971. The BLM Cibola-Trigo Herd Management Area Plan, approved in September of 1980, determined that the Appropriate Management Level for burros is approximately 165, based on “a grazing capacity calculated to restore the vegetative communities within the critical area to approximate original conditions”. The feral burro population within the HMA is, conservatively, over five times the AML and increasing.
Burros consistently tear down/damage fences, feed in refuge restoration project areas and farm fields, make trails through the desert, increase erosion, prohibit natural regeneration of native riparian vegetation, and cause an extreme safety hazard on roads (human injuries and fatalities from collisions with burros). Studies have also found that that feral horses and burros also compete with native wildlife at water sources. The Arizona Invasive Species Strike Team, I&M Program and Imperial and Cibola NWRs assist BLM with annual vegetation monitoring to assess the degree of burro utilization and damage to native plant species in selected areas throughout the Herd Management Area. The Arizona Invasive Species Strike Team coordinator recently entered into an Inter-agency agreement with the Arizona Game and Fish Department to conduct a thorough survey of burros in the Herd Management Area. Better management of feral burros on the landscape will minimize degradation and prolonged long-term impacts to native wildlife and plants and assist managers in improving ecological health, biological integrity and diversity and natural processes and conditions on the refuges.