Restoring Desert Mule Deer in Mexico

Mexico’s wildlife historically has been impacted by land use patterns influenced by socioeconomic and political factors that have resulted in mismanagement of its wildlife resources and a marked decrease in biodiversity. The major threats to diversity are deforestation, mismanagement of livestock, unregulated agricultural enterprises, drainage of wetlands, dam construction, industrial pollution, and illegal exploitation of plant and animal resources. 

Desert  mule deer are one of the most economically and socially important animals in western North America. However in Mexico, populations have shown declines to an extent where they were considered to be in danger of extirpation.   Landowner perspectives have shifted now realizing the value and economic importance of mule deer.  This has translated into protection of the species from illegal hunting and in turn, better conservation.  Big game hunters’ interest in mule deer has contributed to the monetary value of managing for wildlife. 

In an effort to better understand the results of mule deer translocations in the Chihuahuan Desert of Northern Coahuila, Mexico, we began a study that would compare 2 different release methods (hard release vs. soft release) and the development of 2 translocated populations of desert mule deer.

Site fidelity was expressed as the average linear distance between the release site and individual deer locations. Deer were considered “loyal” if the majority of their locations (>50%) were within a 3-mi radius from the liberation site.

Soft-release deer had small home ranges (7,185 acres) and more were loyal (75%) to the release site than hard release deer that had larger home ranges (8,800 acres) and less were loyal (42-60%).  Soft-released deer also had higher survival rates (84%) compared to hard released deer (13-57%).  Mortality was variable across years and release methods, with mountain lions being the primary cause of death for the 2007 hard-release where 46% of deer were predated by mountain lions.  In general, most mortality occurs within the first 6 weeks after release.

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Graduate students with the Borderlands Research Institute transport a recently captured mule deer doe from Texas as part of an effort to restore their populations in northern Mexico.

 

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Home ranges of translocated desert mule deer were smaller and showed more site fidelity using soft-release methods compared to hard release.