Nesting habitat of Belding’s Savannah sparrows in coastal salt marshes

Abstract

Although the Belding’s Savannah sparrow ( Passerculus sandwichensis beldingl ) is listed as endangered in California, little is known about the factors that affect its abundance and distribution. Numbers of breeding pairs, nesting territory sizes, and vegetation characteristics were measured at fourteen study plots in two southern California coastal wetlands, Tijuana Estuary and Los Peñasquitos Lagoon. Sparrows nested in middle salt marsh habitat in areas of dense pickleweed ( Salicornia virginica ) or saltgrass ( Distichlis spicata ). No nesting territories were found in transitional upland or low marsh habitat. Territory sizes were highly variable and significantly larger at Tijuana Estuary. Territory size may be related to nest site availability and water levels at time of establishment. More research is needed on the effects of habitat quality on reproductive success and territory size.