Efforts to Assess the Status of the Tricolored Blackbird from 1931 to 2014

Abstract

The Tricolored Blackbird (Agelaius tricolor; hereafter, also “tricolor”), is unique to California. Among its many salient traits, the tricolor is colonial and often nests in large groups that place heavy demands upon the local biota. Globally, colonial species are believed to be highly vulnerable (Terborgh 1974), and many have become conservation priorities. The tricolor is among these, as it has over the past century suffered a steep population decline due to reductions in its native breeding and foraging habitats and several other factors (Beedy and Hamilton 1997). More recently, elevated rates of mortality of eggs and chicks have resulted from the destruction of breeding colonies during the harvest of their grain field nesting substrates (Meese 2009), and an unknown number of adults is shot in autumn when in mixed flocks foraging in ripening rice with red-winged and other blackbird species (USDA 2013, Meese unpub. data).