Fawn survival and bed-site characteristics of Trans-Pecos pronghorn

The Trans-Pecos historically has been a stronghold for once- diminishing pronghorn fAntilocapra americana) populations in Texas. In the past, the Trans-Pecos herds have supplied the stock for translocation operations to other parts of the state. However, little information has been available on the dynamics, habitat, or home range of these animals. A study was conducted to investigate survival and habitat characteristics of Trans Pecos pronghorn fawns. Survival and home range of adults also were estimated.

Radio telemetry was used to track fawns and adults to locate specific fawn bed sites, estimate adult home range, and to estimate survival of both fawns and adults. Bed sites were measured for various vegetational, topographic, and visibility characteristics and were compared to randomly chosen sites. Bed site characteristics of surviving and nonsurviving fawns, and 3 age groups of fawns were also compared.

Comparisons of micro-habitat characteristics of fawn bed sites and randomly chosen sites suggest that bed sites are selected with greater hiding cover while the fawn is bedded, yet greater visibility while the fawn is standing. Surviving fawns selected sites providing better concealment but selection for brush cover and density decreased with age of the fawn. Fawns were more selective during a year punctuated by drought than in 2 years of above-average precipitation. Overall, fawn bed-site characteristics in the Trans-Pecos differ considerably from those found in more optimal pronghorn habitat in shrub-steppe regions.

Fawn survival was low during the 3-year study and cause of death was primarily attributed to coyote rcanis latrans) predation. However, low fawn survival in the Trans-Pecos may be compensated for by relatively high adult survival, as determined by this study. Home range of adults was greater in the dry year of the study than in the 2 wet years. Home range of females was greater overall than for males.

Results of this study indicate that management of Trans- Pecos pronghorn populations will be enhanced by (1) periodic, short-term, intensive coyote control, (2) studying long-term population trends, (3) monitoring livestock grazing, especially in years following drought, and (4) using previous year's precipitation as a tool to help predict fawn recruitment in the current year.