Historic and Current Status of the American White Pelican Breeding in California

Abstract The American White Pelican (Pelecanus erythrorhynchos) formerly bred the length of California on interior lakes and marshes of the Klamath Basin, Modoc Plateau and Great Basin desert of northeastern California, overflow lands of the Sacramento Valley, terminal lakes in the Tulare Basin of the San Joaquin Valley and at the Salton Sea in the Colorado desert. Historic data are sketchy but nesting is well documented for at least eleven sites. Though unknown, the number of pelicans breeding in the late 1800s and early 1900s may have exceeded 20,000 pairs. Decades of declining numbers and range retraction have left the American White Pelican breeding regularly in California at only two sites in the Klamath Basin (Sheepy Lake on Lower Klamath National Wildlife Refuge and Clear Lake National Wildlife Refuge), where very vulnerable to catastrophic losses. Variably obtained counts at these two sites combined appeared to decrease from about 4,500 nests in 1912 to reach an equilibrium, which fluctuated aroun...