We monitored Streaked Horned Lark reproductive success in the Puget lowlands for four years. Sites included in our research for one or more years included: Ft. Lewis, McChord Air Force Base, and Olympia Airport. The only native prairie site monitored was 13th Division Prairie, which consistently had the lowest reproductive success of all sites. The primary cause of nest failure at 13th Division Prairie and all other sites studied was predation, which accounted for over half of the failed nests. The objective of this study is to identify the potential suite of Streaked Horned Lark nest predators at 13th Division Prairie and use this information to develop a plan for reducing predation rates and increasing overall nesting success.