Pronghorn Restoration Efforts and Survival
Translocating pronghorn has been a common management technique to improve and sustain pronghorn populations in Texas and North America. In fact, since the 1930s almost 6,000 pronghorn have been translocated across Texas. Because of the severity of the declining pronghorn population, we initiated efforts to supplement existing pronghorn herds in the Trans-Pecos. A surplus of pronghorn was identified in the northwest Panhandle of Texas, where pronghorn were depredating agricultural crops. Working with landowners in the Panhandle and Trans-Pecos, we coordinated one of the largest translocations in the state.
Causes of mortality for translocated pronghorn in Trans-Pecos, Texas. The extended drought wreaked havoc on pronghorn survival.
In February 2011, we captured 200 and released 194 pronghorn (176 F, 18 M) to 5 release sites in the Marfa Plateau. Because previous studies had not documented translocation success and we anticipated subsequent translocations, we took the opportunity to monitor site-fidelity, movements, survival, and fawn production of the translocated pronghorn. To monitor mortality and investigate limiting factors affecting their survivability, 80 (40%) pronghorn were equipped with radiocollars (62 F, 18 M).
During the first 8 weeks following release, we documented 26 mortalities primarily from capture myopathy and predation. Food resources started to become more scarce as temperatures began to climb and the body condition of the translocated pronghorn started showing signs of malnutrition. We documented an additional 38 mortalities from April-July that were a combination of predation, Haemonchosis, vehicle collisions, and unknown causes. In late July, the rains returned to portions of the Trans-Pecos stimulating forb growth. Mortalities waned, but the fawn production was nonexistent.
To date, we recorded 63 mortalities of the 80 radio-collared pronghorn (82%). Unknowingly, several natural and climatic events had dramatic impacts on our efforts to restore pronghorn including record setting freezes, drought, heat, and wildfires.
It appears that younger pronghorn were more adaptable to the harsh conditions that prevailed following the release. Despite the outcomes of the translocated pronghorn, translocations will continue to serve as a vital tool in sustaining and recovering pronghorn populations in the future. Results from this effort will be used to further our ability to recover pronghorn populations in the Trans-Pecos.