Date of Award:
5-1-1994
Document Type:
Thesis
Degree Name:
Master of Science (MS)
Department:
Biology
Department name when degree awarded
Biology
Committee Chair(s)
Kimberly A. Sullivan
Committee
Kimberly A. Sullivan
Committee
Edward W. Evans
Committee
Thomas C. Edwards, Jr.
Abstract
I conducted a field study of dominance interactions among a flock of free-living, individually-marked juvenile dark-eyed juncos (Junco hyemalis) to determine if attaining high dominance status conferred any short-term benefits. A priori, I predicted that dominant juvenile juncos in this population would have greater foraging success and spend less time on vigilance behavior than would subordinate juveniles. Hematocrit values, heterophil numbers, and a heterophil/lymphocyte ratio were also documented for each bird to determine whether physiological condition was correlated with dominance status. Dominant juveniles did have greater foraging rates and took less time to handle each food item and thus were more successful foragers than their subordinate conspecifics. Contrary to my a priori prediction, there were no differences in vigilance rates of dominant and subordinate juveniles. Dominant juveniles had higher hematocrit values, fewer heterophils per 100 white blood cells, and lower heterophil/lymphocyte ratios than juveniles subordinate to them, suggesting that dominant birds were in better physiological condition than subordinates. This study documented quantifiable short-term benefits to becoming a dominant member of a flock as a juvenile junco in this population. The next step is to determine whether these short-term benefits can be tied into more long-term benefits such as increased survivorship during the juvenile stage. In addition, a literature review of the importance of dominance interactions to juvenile birds was conducted. Based on this review and the literature on social dominance in adult birds, hypotheses concerning the role of dominance status in survival of the juvenile period were developed.
Recommended Citation
Leary, Joanna, "The Importance of Dominance Interactions to Juvenile Birds" (1994). Biology. 610.
https://digitalcommons.usu.edu/etd_biology/610
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