Helpers are usually male offspring from previous breeding seasons. Helpers participate in all activities, territorial defense, cavity excavation, incubating eggs, feeding nestlings, feeding fledglings and removing fecal sacs. Not only do they forage on pine, they excavate their roosting and nesting cavities in live pine. My study population is located in the Sandhills region of south-central North Carolina. This population has been closely monitored for twenty years by undergraduates, graduate students and research technicians affiliated with North Carolina State University.
Cooperative breeding is a social system in which auxilliary adults participate in raising young.
Helping behavior presents an evolutionary paradox, because these auxilliary adults seem to sacrifice their own reproduction for the benefit of others. This paradox is partially resolved because helpers usually raise offspring who are related to themselves. Incubation and brooding behavior are closely correlated with the hormone, prolactin. I am examining the relationship between plasma prolactin concentrations and nestling feeding behavior of helpers and breeders. Testosterone is a hormone necessary for spermatogenesis, and therefore, successful reproduction, but it also, interferes with parental behavior in some species.