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Allozymic and Morphological Variation in Population Samples of Rufous- Collared Sparrow, Zonotrichia capensis, in Relation to Vocal Dialects
Paul Handford and Fernando Nottebohm
Vol. 30, No. 4 (Dec., 1976), pp. 802-817
Published by: Society for the Study of Evolution
Stable URL: http://www.jstor.org/stable/2407819
Page Count: 16
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Allozymic and morphological variation was studied in relation to vocal dialects in populations of Zonotrichia capensis. The study area was an altitudinal transect on the eastern slope of the Sierra de Aconquija, northwestern Argentina. A banding experiment showed that under the conditions prevailing during 1972-74, adults show a high tendency to return to their previous nesting area. A similar trend is apparent in the smaller number of juveniles banded. Five population samples totalling approximately 200 individuals were taken for variation analysis. Allele frequencies show a clinal pattern in certain of the allozyme systems. The morphological variables show no general common trends. The data are analyzed in terms of incremental change between samples, and it is apparent that a close association exists between allozymic and morphological variation in this regard, while trill variation is unrelated to either of these. These results are discussed, and it is suggested that dialects may be related to areas of abnormally high potential gene flow. It is also possible that certain other environmental factors may be influencing the kind of song changes observed, for example, certain aspects of the auditory environment, and efficiency of sound transmission. Comparisons with another species, Z. leucophrys, indicate that we do not yet have sufficient information to form a unified theory on the significance of song dialects in these two closely related congeners.
Evolution © 1976 Society for the Study of Evolution