Sarah L Kiefer

Learn More
OBJECTIVE Research has demonstrated that veterans with a history of traumatic brain injury (TBI) may experience persistent symptoms following injury. These symptoms are frequently maintained or exacerbated by psychiatric symptoms, including posttraumatic stress disorder (PTSD). Studies suggest that decreasing PTSD symptoms may also reduce postconcussive(More)
Although it has been suggested that testosterone plays an important role in resource allocation for competitive behavior, details of the interplay between testosterone, territorial aggression and signal plasticity are largely unknown. Therefore, we investigated if testosterone acts specifically on signals that communicate the motivation or ability of(More)
Many studies in behavioural endocrinology attempt to link territorial aggression with testosterone, but the exact relationship between testosterone and territorial behaviour is still unclear and may depend on the ecology of a species. The degree to which testosterone facilitates territorial behaviour is particularly little understood in species that defend(More)
Differences in individual male birds' singing may serve as honest indicators of male quality in male-male competition and female mate choice. This has been shown e.g. for overall song output and repertoire size in many bird species. More recently, differences in structural song characteristics such as the performance of physically challenging song(More)
Testosterone has been suggested to be involved in the regulation of male territorial behavior. For example, seasonal peaks in testosterone typically coincide with periods of intense competition between males for territories and mating partners. However, some species also express territorial behavior outside a breeding context when testosterone levels are(More)
The song of oscines provides an extensively studied model of age-dependent behaviour changes. Male and female receivers might use song characteristics to obtain information about the age of a signaller, which is often related to its quality. Whereas most of the age-dependent song changes have been studied in solo singing, the role of age in vocal(More)
In many bird species, song changes with age. The mechanisms that account for such changes are only partially understood. Common nightingales Luscinia megarhynchos change the size and composition of their repertoire between their first and second breeding season. To inquire into mechanisms involved in such changes, we compared the singing of 1-year-old and(More)
On the importance of activity and connectivity of new neurons in the adult zebra finch Inaugural-Dissertation to obtain the academic degree Doctor rerum naturalium Acknowledgements The wonderful three and a half years that I have spent for my PhD thesis at the Animals Behavior Group, first at the Max-Planck-Institute for Molecular Genetics and then at the(More)
  • 1