A plan to poison invasive mice on the Farallon Islands National Wildlife Refuge has received approval from the California Coastal Commission. It now awaits a decision from the regional director of the U.S. Fish and Wildlife Service. The plan would drop 3,000 pounds of poisoned bait from helicopters onto the islands off the coast of San Francisco. The refuge is home to an estimated 300,000 seabirds, including the rare ashy storm-petrel (Oceanodroma homochroa). Biologists say its population is threatened by burrowing owls (Athene cunicularia), which are attracted by an exploding population of mice.