Complete open-access text of [dissertation on ShareOK][1]. Published versions of chapters - Chapter 1 published in [Evolutionary Biology][2] as "An Integrated Framework for Hybrid Zone Models". - Chapter 2 published in [American Midland Naturalist][3] as "Current and Historical Extent of Phenotypic Variation in the Tufted and Black-crested Titmouse (Paridae) Hybrid Zone in the Southern Great Plains". - Chapter 3 published in [Behaviour][4] as "Complex spatiotemporal variation in processes shaping song variation". - Chapter 4 in review at PLoS ONE as "Spatiotemporal structuring of multiple transects across a complex avian hybrid zone". - Chapter 5 published in [Behavioral Ecology and Sociobiology][5] as "Shadow of a doubt: premating and postmating isolating barriers in a temporally complex songbird (Passeriformes: Paridae) hybrid zone". [1]: https://shareok.org/handle/11244/7983 [2]: https://link.springer.com/article/10.1007/s11692-015-9332-9 [3]: https://bioone.org/journals/The-American-Midland-Naturalist/volume-171/issue-2/0003-0031-171.2.271/Current-and-Historical-Extent-of-Phenotypic-Variation-in-the-Tufted/10.1674/0003-0031-171.2.271.full [4]: https://brill.com/view/journals/beh/aop/article-10.1163-1568539X-00003556.xml [5]: https://link.springer.com/article/10.1007/s00265-016-2126-y63-1568539X-00003556.xml