The Purple Martin (Progne subis), designated a species of special concern by the California Department of Fish and Wildlife, has been reported using nest boxes in California only a few times, in contrast to its extensive adoption of nest boxes in Oregon, Washington, and British Columbia and long-term use of them in eastern North America. We installed and monitored nest boxes and artificial gourds at Shelter Cove along California’s northwest coast, where a substantial population of nesting martins is threatened by loss of snags. We placed three nest boxes at one nesting area in 2002, and, after the martins used two boxes in 2007, we added 15 boxes and seven gourds in groups at six other sites early in 2008. From 2008 to 2011, martins used up to 11 boxes and two gourds, as well as nesting in snags, utility poles, and buildings. We monitored their nesting success in 2008, when three of fie occupied boxes successfully fldged young. We also installed boxes or advised on attempts to establish box-nesting colonies at six other sites elsewhere in northern California, none of which were successful. Reasons for failure may include too great a distance from the nearest source population, improper placement, and the martins’
unfamiliarity with a novel type of nest site. Our experiment at Shelter Cove represents the fist successful use of nest boxes designed and placed for Purple Martins in California and suggests boxes may be an effective tool for securing and recovering Purple Martin populations in California.