TPWD News Release — Sept. 21, 2010
The goal of the project is to identify possible causes for the declining pronghorn herds and to evaluate two competing hypothesis regarding pronghorn survival and productivity. Other funding partners include various Chapters of Safari Club International from across the country including the West Texas (Midland/Odessa), Lubbock, Paso del Norte (El Paso), Southern New Mexico (Roswell), and Pittsburgh (Pennsylvania) chapters.
In the desert Southwest, pronghorn populations ebb and flow with rainfall. Pronghorn numbers across the Trans-Pecos have been dwindling since the drought of the 1990s. Once the drought broke, pronghorn and other wildlife populations began to respond with increased reproduction and survival.
However, during the past three years when rainfall provided adequate habitat (food, cover, and water), pronghorn populations have plummeted. In fact, 2010 pronghorn population estimates in the Trans-Pecos are the lowest since the 1970s with an estimated 4,713 pronghorn across the region.
Carter Smith, TPWD executive director, recently attended a meeting of the Pronghorn Working Group (a group of landowners, biologists, hunting guides, and scientists that was formed to help address the declining pronghorn herd).
“The decline of pronghorn in West Texas is a priority for our agency,” Smith said. “The formation of this Pronghorn Working Group and the funding of this grant are the first steps in helping our pronghorn herds.”
The first phase of the study is to evaluate the role of gastrointestinal parasites in pronghorn. Based on sampling efforts in 2009, researchers documented 95 percent occurrence of parasitic round worm (Haemonchus contortus) in hunter-harvested pronghorn. In addition, some of the pronghorn had more than 4,000 individual worms in their stomach. High loads of roundworms can cause anemia in pronghorn, making them weak or even resulting in death. This study will help biologists better understand the relationship between pronghorn and their parasite loads.
The research team will be coordinating a large-scale effort to obtain stomach, blood, and tissue samples from all harvested pronghorn across the Trans-Pecos during the 9-day hunting season that runs from Oct. 2-10. Efforts will also be made to obtain samples from the Texas Panhandle, New Mexico, and Arizona.
The second phase of the study will monitor causes of pronghorn fawns mortality. Predation can be significant in pronghorn populations, especially on fawns. Beginning in spring 2011, researchers will monitor fawn productivity and survival across four core study sites in the Trans-Pecos. By monitoring the fawns, researchers will be able to assess predation and survival. Additionally, biologists will be able to determine if predated fawns have high loads of stomach worms making them more susceptible to predation.
Shawn Gray (Pronghorn and Mule Deer Program Leader for TPWD) and Billy Tarrant (Trans-Pecos District Leader for the Wildlife Division) will be making a presentation “Where have all the pronghorn gone?” on Tuesday, Sept. 28 at 5:15 p.m. in Room 130, Turner Range Animal Science Center at Sul Ross. In the presentation, Gray and Tarrant will provide a brief history of pronghorn, discuss population trends, and outline the steps TPWD and other partners are making to identify the causative factors associated with the decline.
The presentation is sponsored by the Sul Ross Range and Wildlife Club and is open to the public. Light refreshments will be provided following the presentation.