ALLOZYMIC AND MORPHOLOGICAL VARIATION IN POPULATION SAMPLES OF RUFOUS-COLLARED SPARROW, ZONOTRICHIA CAPENSIS, IN RELATION TO VOCAL DIALECTS.

Abstract

Zonotrichia capensis, the rufous-collared sparrow or chingolo, has a very wide distribution; it is found from southern Mexico to Tierra del Fuego, from sea level to over 4000 m and from rain forest edges to desert scrub. Hence it has been an attractive subject for studies of variation, for example subspecific taxonomy, breeding strategies and moult patterns (Chapman, 1940; Miller, 1961; Miller and Miller, 1968; Wolf, 1969; Davis, 1971; King, 1972a, 1973a, 1973b). In addition, work has been carried out on the geographical variation of its song (Nottebohm, 1969, 1975; Egli, 1971; King, 1972b; Nottebohm and Nottebohm, in press) and on song ontogeny. A pilot experiment by Egli (1971) suggests that the song of Z. capensis is learned by reference to auditory information acquired during the first 40 days after hatching. This result is in agreement with earlier observations on song ontogeny in a close relative, the North American whitecrowned sparrow, Z. leucophrys, which also shows local dialects (Marler and Tamura, 1962, 1964). Over most of its range the song of the rufous-collared sparrow is composed of one to five usually dissimilar introductory whistles, followed by a series of identical repetitions of another, usually briefer note. The introductory whistles often vary considerably between individuals singing at the same locality, and determine the theme sung by each bird. The terminal trill can remain relatively homogeneous