Belding’s Savannah Sparrow (Passerculus sandwichensis beldingi)

State Listed Endangered Species

Belding’s Savannah Sparrow by L. Hays

The Belding’s savannah sparrow ( Belding’s) is one of four subspecies of savannah sparrows that is otherwise widely distributed and occur in a variety of habitat types, including grassland, high-elevation meadow, and marshes. The Belding’s savannah sparrow is unique in that it represents one of only two wetland-dependant avian species endemic to coastal salt marshes in southern California. This species is a year-round resident of these salt marshes, and is therefore reliant upon these habitats to meet all of its life history requirements. This race ranges along the southern California coast from Santa Barbara County (Goleta Slough) in the north into Baja California, Mexico (near El Rosario) in the south.

The Belding’s savannah sparrow is a small brown sparrow with fine streaking on the head and face, a pale beige to white belly, and often shows a dark central breast spot. As with most ground dwelling species, this bird is inconspicuous and blends well with its environment. The most distinguishing characteristic is the yellowish color of the lores (area between the bill and eyes).

The main factors that influence the long-term survivability of this subspecies are the health and security of its habitat. In southern California, the long-term protection of coastal salt marsh habitat is closely tied to ownership and use of the land. Threats of salt marsh habitat loss or degradation have slowed but continue. Other threats include problems associated with human trespassing, pets within the marshes, encroachment from adjacent human activities, and habitat degradation.

This subspecies was listed as endangered by the State of California in 1974 due to the development, degradation, and fragmentation of coastal salt marsh habitat as numbers of Belding’s savannah sparrows decreased dramatically.

Because of the secretive nature of this sparrow, it can be difficult to obtain accurate population estimates. Given the right habitat conditions, territory size may be small and breeding pairs may occur in relatively high concentrations. Census techniques consist of searching for territorial males in suitable habitat during the breeding season (late March through early July). Territorial behavior is ascertained through detection or observation of singing, scolding, aerial chases, nest-building, feeding young, or extended perching of individuals or presumed mates perching together in an area.

The Belding’s Savannah Sparrow population in California increased from 1,084 pairs in 1973, 1,610 pairs in 1977, 2,274 pairs in 1986, 1,844 pairs in 1991, 2,350 pairs in 1996, and 2875 pairs in 2001. However, statewide censuses of Belding’s savannah sparrows reveal wide fluctuations in local population sizes, with local extinctions occurring in some years. The population at Bolsa Chica has been more regularly censused and the population has been fluctuating between 100 and 250 breeding pairs.