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Endangered Mice Relocated From San Diego Zoo To Coastal Wilderness

Photo credit: San Diego Zoo Global

Pacific pocket mice, which make their homes underground, are about to be relocated into an area of Laguna Coast Wilderness Park in California, June 7, 2016.

Fifty endangered mice are scheduled for relocation to the Orange County coast, according to San Diego Zoo Global.

Pacific pocket mice, which make their homes underground, are about to be relocated into an area of Laguna Coast Wilderness Park. It's the first relocation for the Pacific pocket mouse recovery program, which is managed by staff at the San Diego Zoo Institute for Conservation Research, in cooperation with the U.S. Fish and Wildlife Service.

"This collaborative effort between federal, state, and regional partners has been instrumental in helping this critically endangered mammal take this important step toward recovery,'' Mendel Stewart, field supervisor for the U.S. Fish and Wildlife Service's Carlsbad office, said in a statement.

"We also appreciate the stewardship of the U.S. Marine Corps and Center for Natural Lands Management for their ongoing management of this species' habitat and supporting the captive breeding effort,'' according to Stewart.

Pacific pocket mice are critical to their ecosystem function, because they are seed eaters that disperse the seeds of native plants throughout their habitat, according to a statement released by San Diego Zoo Global. They also dig burrows that hydrate and increase nutrient cycling in the soil that encourages growth of native plants.

This nocturnal species was thought to be extinct in the 1980s, but it was rediscovered in 1993. In 2011, together with conservation partners, San Diego Zoo Institute for Conservation Research decided that the species couldn't be recovered by keeping the Pacific pocket mouse in the wild.

In June 2012, 30 adult Pacific pocket mice were taken from the three remaining wild populations along the California coast to participate in a breeding program at an off-exhibit area at the San Diego Zoo Safari Park.

The breeding program was designed to increase the overall population, while maintaining genetic diversity in the species. In the wild, the three Pacific pocket mouse habitats are separated by human development, so there was no chance for these populations to interbreed.

Pacific pocket mice have very strict habitat requirements and they live only within four miles of the coast. Their historic range is a stretch of coastal land extending from the El Segundo dunes near Los Angeles International Airport to the Mexico border. The area within Laguna Coast Wilderness Parks is part of the native habitat for this species.

"It's thrilling to be a part of the reintroduction of the Pacific pocket mouse into its historic range, and to know that their return will also bring about growth for the native plant species that live here,'' said Lisa Bartlett, chairwoman of the Orange County Board of Supervisors and vice chair of the Foothill/Eastern Transportation Corridor Agencies.

Biologists from San Diego Zoo Global will be monitoring the Pacific pocket mice to ensure that the animals are acclimating and thriving in the new area.

"This is a historic moment for the Pacific pocket mouse -- establishing a fourth population in Laguna Coast Wilderness Park -- and it is so exciting,'' said Debra Shier, associate director of applied animal ecology for the San Diego Zoo Institute for Conservation Research. "It's a huge responsibility to pull animals out of the wild and into captivity.''

"We prefer to keep them in the wild,'' she said. "But for the Pacific pocket mouse, it got to a point we couldn't recover the species by keeping them in the wild.''

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