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Date of Award


Document Type


Degree Name

Master of Science (M.S.)


Biological Sciences

First Advisor

Lee Christianson

First Committee Member

A. Mathias

Second Committee Member

M. D. Arvey


Sexual dimorphism has been noted to exist in many genera of birds, but it is not until recently that papers have appeared which deal with the actual extent of sexual dimorphism and its possible adaptive significance. The papers of Rand (1952), Sibley (1957), Amadon (1959), and Selander (1966) hypothesize about the possible significance of sexual dimorphism in birds, and the papers of Kilham (1965), Selander (1965), Storer (1966), Ligon(1968), Ingolfsson (1969), and Verner and Willson (1969) examine the relationship between hypotheses on the significance of sexual dimorphism and actual field conditions. None of these papers deals with differences in bone or muscle ratios which may exist between the sexes. A paper by Engels (1938a) on variation in bone length and limb proportion in the coot does examine differences in bone length and limb proportions due to sex, but only in a very cursory manner.

It appears that only the most obvious and well known sexually dimorphic birds, i.e. woodpeckers, birds-of-paradise, accipitrines, have been studied. In this paper my purpose is to ascertain osteological and myological differences between the sexes of a bird which does not have a great deal of apparent sexual dimorphism - Sturnella neglecta neglecta Audubon, A.O.U. 501.1.



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