DIFFERENCES IN SINGING BEHAVIOR BETWEEN RUFOUS-COLLARED SPARROWS IN COSTA RICA AND NORTHWESTERN ARGENTINA

The Rufous-collaredS parrow (Zonotrichia capensisis) one of the most common passerine species in Latin America, ranging from southern Mexico to Tierra de1 Fuego. Although there are studies on the vocal behavior of this species from several locations across SouthAmerica (see King 1974, Nottebohm 1975, Tubaro et al. 1993), most have concentrated on populations in northwestern Argentina (Nottebohm 1969, King 1972, Handford 1988, Lougheed and Handford 1992). Males within these populations sing songs that have two distinctparts: an introductory theme, consisting of one to five usually dissimilar whistles, and a terminal trill, made from a series of repeated, morphologically similar notes (Nottebohm 1975). In northwestern and westcentral Argentina, song dialects in Rufous-collaredSparrows are defined by quantitative variation in trill rate (Nottebohm 1969), and map closely onto patterns oforiginal natural vegetation (Nottebohm 1975, Handford 1988).

JAMES R . FOTHEIUNGHAM, The Condor 97: 821-826