Earlier this week, 50 federally endangered Pacific pocket mice (Perognathus longimembris pacificus) were released in California’s Laguna Coast Wilderness Park as part of a project led by scientists at the San Diego Institution for Conservation Research. The effort began four years ago, when scientists with the San Diego Zoo began collecting the mice as part of a captive breeding program to help reestablish the population. The species, once thought to be extinct, has faced the threat of urban development. The scientists inserted tiny microchips into the mice to track and study them after the release. Read more about this recovery effort at the Orange County Register.