Evolution and Ecology of Feather Molt in Birds

Feathers are a key innovation for birds because they provide many different functions for birds. Feather replacement strategies must balance the immediate needs for feathers with loss of function during molt. Birds show a diversity of molt strategies, but the evolution and mechanisms for this diversity have not been investigated. My research focuses largely on the evolutionary patterns and exogenous drivers of the diversity of molt strategies in birds.

Representative publications:
     Ryan S. Terrill. ​2020. Simultaneous Wing Molt as a Catalyst for the Evolution of Flightlessness in Birds. The American Naturalist 196 (6), pp 775-784. [full text]
     Ryan S. Terrill, Seeholzer, Glenn F., and Wolfe, Jared D. 2020. Evolution of breeding plumages in birds: A multiple-step pathway to seasonal dichromatism in New World Warblers (Aves: Parulidae). Ecology and Evolution 10 (7) 9223-9239. [Open Access]
     Ryan S. Terrill and Allison J. Shultz. 2021. On the multifunctionality of feathers and the evolution of birds. [EcoEvoRxiv preprint]
     Ryan S. Terrill, Youyi Fong, Jared D. Wolfe, and Amanda J. Zellmer. 2021. Threshold models improve estimates of molt parameters in datasets with small sample sizes. Ornithology. ukab038  ​[full text]
     Ryan S. Terrill. 2018. Feather growth rate increases with latitude in four species of widespread resident neotropical birds. The Auk: Ornithological Advances 135. [pdf]

Distributions and Natural History of Tropical Birds

I am broadly interested in the distributions, life history, and natural history of birds, with a focus on the New World Tropics. My research in this topic focuses on field, ecological, and genomic work to understand the spatial and temporal distributions of birds and their annual cycle events; with a particular focus on poorly-studied regions, and anthropogenic influence on changes in space and time use. 
Current project website: The Mexican Bird Resurvey Project

Representative publications
     Ryan S. Terrill, Christine A. Dean, John Garrett, Daniel J. Maxwell, Lauren Hill, Andrew Farnsworth, Adriaan Dokter, and Morgan W. Tingley. 2021. A novel locality for the observation of thousands of passerine birds during spring migration in Los Angeles Co., CA. ​Western Birds 52:322:229 [pdf]
     Ryan S. Terrill, Maley, James M., Tsai, Whitney L.E., Fistanic, Kevin B., Freeland, Rowdy J., Franceschelli, Anna, Lewis-Smith, Bryce, Lu, Leeza, and Yoder, Jeremy P. 2019. Tricolored Blackbirds feeding in Joshua Tree inflorescences. Western Birds 50: 180:182 [pdf]
     Ryan S. Terrill, Aponte Justiniano, M.A., Harvey, M.G., Seeholzer, G.F., and Strem, R.I. 2014. Notes on the avifauna of the floodplain forest of the Río Mamoré, Beni, Bolivia, with a description of the juvenile plumage of the Unicolored Thrush (Turdus haplochrous)(Aves:Turdidae). Occasional Papers of the LSU Museum of Natural Science 81: 1-21. [pdf]
     Daniel F. Lane, Miguel Angel Aponte Justiniano, Ryan S. Terill, Frank E. Rheindt, Luke B. Klicka, Gary H. Rosenberg, C. Jonathan Schmitt, Rosalyn Price-Waldman, and Kevin J. Burns. 2021. A distinctive new genus and species of tanager (Passeriformes, Thraupidae) from the lower Yungas of western Bolivia  and southern Peru. Ornithology. ukab059. [full text]
     Jessica A. Oswald, Ryan S. Terrill, Stucky BJ, LeFebvre MJ, Steadman DW, Guralnick RP, Allen JM. 2021. Ancient DNA from the extinct flightless Haitian cave-rail (Nesotrochis steganinos) suggests biogeographic connection of the Caribbean and Old World. Biology Letters 17.3: 20200760. [online full text and pdf]
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