After breeding and releasing almost 100 endangered Pacific pocket mice, researchers discovered mice reintroduced into Orange County's Laguna Coast Wilderness Park have started breeding on their own, according to the San Diego Zoo.
U.S. Fish and Wildlife Service and California Department of Fish and Wildfire released a new group of 25 pocket mice last month into a 1.6-acre fenced section of the park. The offspring have also begun breeding.
"This is a major milestone for a program that has so many delicate and important stages," said Debra Shier, Ph.D., Brown Endowed Associate Director of Recovery Ecology at the San Diego Zoo Institute for Conservation Research. "There are four major stages for reintroducing a species to the wild: release, establishment, growth and regulation. Right now, we have reached the growth phase for this population. I think if we continue on this trajectory, we will have successfully established a new population in the wild."
Breeding facilities use air conditioning and humidifiers to mimic coastal temperature and humidity levels the mice require to prepare them for the wilderness. Researchers will continue to provide supplementary food to the mice as they navigate the wild terrain.
Scientists consider these mice vital to their ecosystem because they seed disperse for native plants throughout their habitat, according to the San Diego Zoo.
The Pacific pocket mouse breeding program started in 2012 and took 34 adult Pacific pocket mice from three remaining wild habitats to an off-exhibit area at the San Diego Zoo Safari Park, according to the San Diego Zoo.
The programs managed by staff at San Diego Zoo Institute for Conservation Research, working closely with U.S. Fish and Wildlife Service, California Department of Fish and Wildfire and OC Parks.
The Pacific pocket mouse is the smallest in North America, weighing six and seven grams. It’s currently listed as Endangered under the U.S. Endangered Species Act.