This research asks how animals know whether and when to migrate and when to breed. The focal animal is a songbird in which populations with separate breeding ranges winter together but differ in whether or not they migrate. When spring arrives the non-migrants begin to breed, while the non-migrants delay breeding despite living in the same environment. Research on the mechanisms that account for different responses to identical environments could help to explain how animals monitor the environment and adjust their physiology to their needs. The dark-eyed junco is a songbird and an ideal model to address these questions.
This project will investigate plasticity in hormone systems using hormonal "challenges" and pharmacological manipulations. It will also explore differences in gene expression between resident and migratory juncos from recently diverged populations (California) and longer diverged populations (in Virginia) that over-winter together but breed in different places at different times. The prediction is that migrants will differ from residents in their response to challenges and that recently diverged populations will differ less than populations that diverged longer ago. Another prediction is that gene expression in a common garden will differ between longer diverged populations as compared with recently diverged populations.
Broader impacts The research will enhance understanding of why and how some animals are able to thrive in changing environments, while other animals' ranges retreat, and some species are lost. This research will provide numerous opportunities to train graduate and undergraduate students, and knowledge gained will be disseminated broadly. The project will enable promotion of a documentary film starring the study species and designed for use in high schools and public venues for adult learners.
Data Management. Data supporting results in published papers will be made available on Genbank and/or Dryad. All data generated from this research will be archived in an online repository maintained by the Indiana University Library (https://scholarworks.iu.edu/dspace/handle/2022/7911).
