My master's thesis encompassed my two main research interests: animal behavior and conservation biology. Specifically, I examined whether stress hormones play a role in the reproductive inactivity of subordinate helper red-cockaded woodpeckers (Picoides borealis), and whether the presence of many group members influences the stress hormone levels of these birds. Since red-cockaded woodpeckers largely reside on military installations (because these federal lands are protected from deforestation), I also investigated whether military training activities influence stress hormone levels in this species.
As it turns out, stress hormone levels don't appear to mediate sexual inactivity in helper males of this species. However, I found that stress hormone levels are lower in all males living in family groups with two or more helpers compared to those living in smaller groups. This may suggest that the presence of many helpers reduces the amount of energy expended, in the form of offspring care and territory defense, by all males in a family group.
Interestingly, I also found that stress hormone levels are lower in birds residing in areas of frequent, high-intensity military activity than in those living in areas of infrequent activity. At this point it is difficult to determine what, if any, long-term effects could arise from such down-regulation of hormone levels.
Department of Biology
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