California is one of the richest and most threatened reservoirs of biodiversity on earth (Conservation International 2004: www.biodiversityhotspots.org/xp/Hotspots/california_floristic/ So it should come as no surprise that on a global scale the state itself may be viewed as an important bird area, if not for its wealth and diversity of bird species and subspecies, many of which are in jeopardy, then for its high level of endemism (Stattersfield et al. 1998). Inevitably, some areas within the state are more important for birds than others—but only recently has there been a focused effort to identify and describe these areas, let alone protect them.