The California Least Tern (Sterna albifrons browni) is on the Department of the Interior’s endangered species list. The survival of this tern is in jeopardy due to intensive urban development of its nesting sites and nearly constant human disturbance during nesting. Except for two remnant colonies, the only natural nesting sites remaining in the state of California are located at the mouth of the Santa Margarita River on Marine Corps Base, Camp Pendleton, in San Diego County (Craig, pers. comm.).