Weekly Update: Arizona Sheep Project


Last year, SCI Foundation partnered with the Arizona Game and Fish Department (AGFD) to establish a self-sustaining population of desert bighorn sheep in the Santa Catalina Mountains near Tucson, Arizona. This conservation effort has scheduled three separate releases of bighorn sheep, each consisting of approximately 30 animals. Biologists estimate that the Catalina Mountains can sustain a population of about 110 sheep.

The first release took place in November 2013. It consisted of 31 sheep, 21 adult females (ewes), three yearling ewes, five adult males (rams), and two yearling rams. Thirty of the released sheep were outfitted with satellite GPS collars to provide managers with up-to-date information to help make adaptive, data-driven management decisions. As of 12 November 2014, only 12 of the collared sheep are known to be alive. Mountain lions killed at least 15 of the reintroduced sheep, which means they are a very influential predator in this landscape.

Realizing that predation is the single greatest threat to establishing a successful sheep population, Arizona has developed an Adaptive Mountain Lion Management Plan.  The plan now allows for the administrative removal of any mountain lion(s) that prey on bighorn, except for females with spotted kittens. Hopefully this management action will reduce mountain lion predation on transplanted bighorn sheep.


Recently, additional sheep were introduced to the population through supplemental releases conducted on November 19 and 20, 2014. The 12 remaining sheep from the 2013 release were joined by 23 ewes and 7 rams, all of which were fitted with GPS collars. As of December 3, 2014, all 42 collared sheep are alive.

Understanding how these sheep use their environment and interact with predators is central to their conservation. The radio collars tell scientists what habitat characteristics are most important to bighorn sheep. This allows conservationists to pinpoint the most optimal release areas and develop better management plans for those specific habitats.

If successful, this effort would mark the sixth mountain range in which the Arizona Game and Fish Department has established a naturally reproducing population of bighorn, living in contact with existing populations of mountain lions. SCI Foundation is proud to participate in such a large scale project and looks forward to seeing the bighorn population flourish in the Catalina’s.


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