Meeting Abstract

109.3  Sunday, Jan. 6  It’s Complicated: Testosterone Production, Aggression, and Parental Care in Male Northern Cardinals DEVRIES, MS*; WINTERS, CP; HOLBROOK, AL; JAWOR, JM; University of Southern Mississippi margaret.devries@eagles.usm.edu

Interrelationships of testosterone (T), male aggression, and paternal care have received much investigative attention. Many studies have focused on examining such relationships with avian species characterized by relatively brief periods of territoriality and breeding. Few have investigated links between circulating T and reproductive behavior with birds that are year-round territorial residents and have lengthy breeding seasons, such as the Northern Cardinal Cardinalis cardinalis. Here, we report findings from a 4-year project with the male cardinal examining aspects of T production and potential interconnections with circulating T, aggression, and paternal care. Our work suggests that male cardinals have the physiological capacity to significantly increase T levels during non-reproductive periods in response to standardized gonadotropin-releasing hormone (GnRH) injections. Male cardinals maintained the ability to significantly elevate T following GnRH injections across the pre-breeding and breeding seasons; yet, circulating T levels were not significantly higher following simulated aggressive encounters and no relationship existed between T concentrations and the degree of paternal care provided by individuals. This lack of relationship between relative circulating levels of T and behavioral performance suggests a complex association between T and reproductive behavior among males of this species. Whether this complicated relationship of circulating T and male behavior is unique to the cardinal or characteristic of other temperate resident species exhibiting a similar behavioral ecology is unknown and deserves greater attention.