Cultural Change and Geographic Variation in the Songs of the Belding's Savannah Sparrow (Passerculus sandwichensis beldingi)

Abstract

The Belding's Sparrow is a subspecies of the Savannah Sparrow that <br /><br />occurs only in isolated patches of Salicornia marsh habitat between Goleta, Cal- <br /><br />ifornia and El Rosario Lagoon, Baja California Norte. Song samples were obtained <br /><br />from 14 local populations during 1973 and 7 populations were resampled during <br /><br />1987/88. Turnover in the element lexicon of each population was low. A few <br /><br />elements changed in their proportional occurrence rate. During the initial survey <br /><br />it was noted that certain song types were common among males at any one locality. <br /><br />After 1 5 or 1 6 years the most common (popular) types in some populations remain <br /><br />dominant. At other localities types have changed in popularity. Sequence com- <br /><br />parison analysis of elements within songs was conducted to produce an objective <br /><br />inter-song dissimilarity matrix. This analysis revealed that song variation within <br /><br />local populations is much less extensive than among populations. The features <br /><br />used to define the original dialects remain distinctive of the local populations.