Postdoctoral Fellow / Migratory Bird Center
My current research focuses on the impacts of dams on nutrient subsidies to freshwater food webs from marine environments. I am utilizing stable-isotopes to track the ecological impacts of these impediments to salmon migration, and thus marine derived nutrients, on both aquatic and terrestrial food webs. I am focusing this research on an aquatic consumer, the American Dipper, as well as a terrestrial riparian consumer, the Warbling Vireo, on the Olympic Peninsula of Washington State. In addition, I am using tree ring analysis to look at the impacts of dams on riparian ecosystems over a longer time scale. This research is taking place in the context of the largest dam removal project in US history on the Elwha River."
Tonra, Christopher M., Marini, Kristen L. D., Marra, Peter P., Germain, Ryan R., Holberton, Rebecca L. and Reudink, Matthew W. Color expression in experimentally regrown feathers of an overwintering migratory bird: implications for signaling and seasonal interactions, Ecology and Evolution, 4 (8) 1222-1232. 2014.
Tonra, Christopher M., Marra, Peter P. and Holberton, Rebecca L. Experimental and observational studies of seasonal interactions between overlapping life history stages in a migratory bird, Hormones and Behavior, 64 (5) 825-835. 2013.
Angelier, Frédéric, Tonra, Christopher M., Holberton, Rebecca L. and Marra, Peter P. Short-term changes in body condition in relation to habitat and rainfall abundance in American redstarts Setophaga ruticilla during the non-breeding season, Journal of Avian Biology, 42 (4) 335-341. 2011.
Tonra, Christopher M., Marra, Peter P. and Holberton, Rebecca L. Migration phenology and winter habitat quality are related to circulating androgen in a long-distance migratory bird, Journal of Avian Biology, 42 (5) 397-404. 2011.
Tonra, Christopher M., Marra, Peter P. and Holberton, Rebecca L. Early elevation of testosterone advances migratory preparation in a songbird, Journal of Experimental Biology, 214 (16) 2761-2767. 2011.