Free-living male Mountain White-crowned Sparrows exhibit territorial aggression without modulating total or free plasma testosterone

Sharon E. Lynn, Thomas P. Hahn, Creagh W. Breuner

    Research output: Contribution to journalArticlepeer-review

    Abstract

    In some species, expression of territorial aggression is accompanied by a rise in testosterone secretion, but in others aggressive behavior is expressed while testosterone levels remain unchanged. Corticosteroid binding globulin (CBG) binds both corticosterone and testosterone in avian plasma. Thus, increasing corticosterone may result in fluctuations in unbound ("free") testosterone; this could result in greater biological activity of testosterone without an increase in testosterone secretion. We investigated whether such plasma interactions of testosterone, corticosterone, and CBG might result in alterations of free testosterone in male Mountain White-crowned Sparrows (Zonotrichia leucophrys oriantha). We conducted simulated territorial intrusions during incubation and compared total and free testosterone of males captured immediately following a simulated territorial intrusion with that of males captured passively. All experimental males showed aggressive behavior, but apparently did not modulate total or free testosterone relative to controls.

    Original languageEnglish
    Pages (from-to)173-180
    Number of pages8
    JournalCondor
    Volume109
    Issue number1
    DOIs
    StatePublished - Feb 2007

    Keywords

    • Aggression
    • Corticosteroid binding globulin
    • Free hormone
    • Simulated territorial intrusion
    • Testosterone
    • Zonotrichia leucophrys oriantha

    Fingerprint

    Dive into the research topics of 'Free-living male Mountain White-crowned Sparrows exhibit territorial aggression without modulating total or free plasma testosterone'. Together they form a unique fingerprint.

    Cite this