BELDING'S SAVANNAH SPARROW 715 



lucid and succinct statement on this interesting racial complex. In 

 order that the following accounts may receive a proper foundation 

 and perspective, his statement follows: 



Along the Pacific coast of Baja California from the international boundary 

 south to Magdalena Bay, on the San Benito Islands, and on the coast of north- 

 western Mexico from the mouth of the Colorado River south to Sinaloa, there 

 exists a series of populations of the Savannah Sparrow (Passerculus sand- 

 wichensis) which are separated ecologically from those of the interior of the con- 

 tinent. The habitat of this group, save for two instances of insular adaptation, 

 is rather rigidly restricted to tidal marshes, a fact long recognized and reflected 

 in past vernacular usage of the name "Marsh Sparrow." Because of environ- 

 mental Hmitations, distribution is not continuous and through the same cir- 

 cumstance the transition from one population to another tends at times to be 

 more abrupt in one or more characters than otherwise would be the case. This 

 abruptness is expressed in the nomenclature of only a few years ago, as witness 

 the binomials Passerculus beldingi, Passerculus rostratus, and Passerculus guitatus. 



Considerations which have altered the concept of closely related but distinct 

 species are the discovery of geographically intergrading populations in some 

 cases and breakdown of supposed specific characters through individual variation 

 in others. There now is no valid reason to dispute the revaluation of these initially 

 conceived species as geographical variants of the continentwide Savannah 

 Sparrow, Passerculus sandwichensis. 



This race of the Savannah sparrow is a permanent resident and 

 abundant occupant of the coastal salt marshes from Santa Barbara 

 south through San Diego County. Karely, the race extends inland 

 to alkaline marshes as much as 8 miles from the coast, but such 

 localities are usually within 100 feet of sea level. The range continues 

 to the Todos Santos Islands, El Rosario, in Baja California. 



Nesting. — W. L. Dawson (1923) commented on the colonial nesting 

 of beldingi and mentions a 5-acre stretch of salt marsh that harbored 

 about 20 pairs in April. Nesting occurs in April and by May 1 

 most of the broods have hatched. Nests are difficult to find unless 

 the adult sits closer than usual and flushes at close range. When 

 the colony is aroused the females seem to slip away at long range 

 and a person may search for an hour among 40 pairs of birds without 

 finding a nest. A female flushed at close range flutters over the tops 

 of the plants for a great distance as though seeking to decoy, but 

 if the nest is approached she will not return nor evince further 

 interest. P. s. beldingi nests indifferently in the shelter of the sali- 

 cornia itself, or in the protection of nearby larger growth. The 

 nest is settled firmly upon the ground among interlaced stems or 

 grasses and under adequate cover of grass or weed. One nest was 

 composed of dried salicornia stems and lined with duck feathers. 

 Another nest, deeply cupped, was composed of fraj'ed weed stems 

 and finely woven grasses, with a single horsehair. 



