Survey of Wild Cats and Other Carnivores

Carnivores, including bobcats, are an important component of native rangelands and are an indicator of an overall ecosystem health. The East Foundation is committed to conducting research that makes a difference, including threats to the productivity of native rangeland – threats such as frequent and reoccurring drought.

We conducted camera trapping on the San Antonio Viejo, Buena Vista, and Santa Rosa ranches from February 2012 to July 2014 to determine the effects of drought and coyote presence on bobcat density. We used 84 infrared-triggered digital cameras to monitor stations – 29 stations at the San Antonio Viejo Ranch, 26 stations at the Buena Vista Ranch, and 29 stations at the Santa Rosa Ranch. During the 28-month continuous field season, we logged 48,166 total camera station nights.

We recorded and analyzed:

  • 730 photographs of bobcats, which included 149 unique individuals
  • 4,008 photographs of coyotes
  • Precipitation and related Palmer Modified Drought Index
  • Vegetation and related Normalized Difference Vegetation Index

We found:

  • Average bobcat density for the San Antonio Viejo was 1/553 acres
  • Average bobcat density for the Buena Vista Ranch was 1/880 acres
  • Average bobcat density for the Santa Rosa Ranch was 1/751 acres
  • Drought and the presence of coyotes had no effect on bobcat density

Across East Foundation lands, bobcat densities were remarkably stable – bobcats were resilient to changing drought conditions and coyote presence. Overall, bobcat densities were high and similar to other regions of Texas. The East Foundation is committed to healthy rangelands and wildlife populations. Severe drought does not appear to threaten bobcat populations in South Texas.

Partner: Caesar Kleberg Wildlife Research Institute

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