The Bank Swallow (Riparia riparia) has been recorded in the lowlands of California since ornithologists began to explore these areas in the mid-nineteenth century (Grinnell and Miller 1944). Newberry (1857) considered the species to be common throughout California during his era. Today, Bank Swallows are locally common only in certain restricted portions of their historic range where sandy, vertical bluffs or riverbanks are available for these colonial birds to construct their nest burrows. The Bank Swallow nests in earthen banks and bluffs, as well as sand and gravel pits.
Bank swallows utilize vertical eroding banks
Sharon Beals, Bank Swallow Nest, Riparia riparia, 2007, Pigment ink on Etching paper, Nest in the collection of the California Academy of Sciences, San Francisco
Photo by: Heather Proctor. Bank Swallows prefer freshly eroded banks as older burrows may contain heavy parasite loads
Since 1986 the CDFW (in partnership with the USFWS since 1999) has conducted annual surveys along the Sacramento River between Red Bluff and Colusa
Agency revetment placed on an eroding bank on the middle Sacramento River under Executive Order S-01-06. Photo by Joe Silveira (USFWS), 2007
The natural river processes of erosion and deposition maintain Bank Swallow habitat. Photo by: Stacy Cepello
The Bank Swallow is primarily a riparian species throughout its North American and Eurasian breeding range. Once locally abundant in suitable habitats, numbers have declined statewide in recent years. It is now absent as a breeding bird in southern California. A Department of Fish and Wildlife study of the statewide population of Bank Swallows in 1987 found that the current population center for the species is along the Sacramento and Feather Rivers in the Sacramento Valley. Other concentration areas include the Klamath Basin and Modoc County areas in northeastern California. Most historical records of Bank Swallow nesting colonies were from central and southern California, where populations no longer exist. During 1987, only four colonies were found south of San Francisco Bay. The Sacramento River and Feather River populations comprise about 64 percent of the colonies and 70-90% of the California population.
Bank Swallow (Riparia riparia) near a nest entrance
Bank Swallow (Riparia riparia)
A colony nesting on an eroding, vertical bank on the Sacramento River