The group known as the new world nine-primaried oscines is a large and diverse group containing about 10% of the living species of birds. The group is poorly known karyologically and phylogenetic relationships of some species within the group remain uncertain. In this paper, karyological data relating to the relationships of three species are presented. The data is also useful for exploring the nature of chromosomal evolution in birds. Two species of Parulinae were studied, with other warblers for comparison. Karyological data strongly supported removal of the Olive Warbler, Peucedramus taeniatus, from Parulinae. The Yellow-breasted Chat, Icteria virens, was found to be aberrant but properly a member of Parulinae. The genus Dendroica was found karyotypically conservative, with no differences between four species. The genus Vermivora was distinguished from other genera by large blocks of heterochromatin at the centromeres of most macrochromosomes. It appears that the Five-striped Sparrow, Amphispiza quinquestriata, is properly placed in its genus according to analysis of a data set that combined karyological and morphological data. This work strongly suggests that Chromosomal evolution is decoupled from the speciation process in Emberizidae. More intrageneric karyotypic variation was found within Emberizinae than has been previously reported from any bird taxon. There was a great deal of karyotypic rearrangement between species in Thraupinae and Cardinalinae. The rearrangements appear to be due to pericentric inversion. The heteromorphisms in the karyotypes of A. quinquestriata and Pipilo erythrophthalmus when combined with reports of heteromorphisms in other nine-primaried oscine species suggest this group has mechanisms to avoid meiotic irregularities usually associated with pericentric inversion. Further karyological studies of the nine-primaried oscines are required to improve our understanding of chromosomal evolution in the group.

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Thesis (Ph. D.)--University of Nevada, Reno, 2008. / "December 2008." Includes bibliographical references. Online version available on the World Wide Web.

Thesis (doctoral)--University of Stockholm, 1984. / Cover title. Added t.p. laid in. Includes bibliographical references (leaves 24-26 (1st group)).

Sexual selection is usually invoked to explain the evolution of elaborate epigamic characters in animals. However, the mechanism by which female choice operates is poorly understood, and it is not clear whether female choice is purely aesthetic or related to male genotypic quality. It has been suggested that Moller's fluctuating asymmetry (FA) hypothesis may resolve the 'arbitrary trait'-'good gene' debate. However, tests of this controversial hypothesis have yielded equivocal results. I examined the allometric patterns of FA in the redcollared widow in order to test the FA hypothesis. In addition, I documented intrapopulation variation in trait size to determine whether females could distinguish between males on the basis of ornament size and/or symmetry. Male tail length was found to be more variable in size than other traits, suggesting that sufficient variation exists in ornament size for females to distinguish between males on this basis. In addition, the prediction of the FA hypothesis that ornaments would display higher degrees of asymmetry than non-ornamental traits was supported. However, no significant linear or second-order polynomial relationship was found between trait size and asymmetry for tail, wing and tarsus length. Furthermore, neither tail length or symmetry was correlated with indices of body condition. Although this might suggest that the FA hypothesis is invalid, I argue that the assumptions of the hypothesis are too simplistic for it to hold true for all species without taking the basic biology of the species into account. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1997.