Erica J. Kim


My son (taking a nap in an awkward position, as he is wont to do!) and I

I am a Ph.D. candidate in UC Berkeley’s Biophysics Graduate Group, studying the flight mechanics of Calypte anna in the Animal Flight Laboratory. Specifically, my thesis focuses on Anna’s hummingbirds performing previously unstudied flight behaviors, such as hovering near ground surfaces and high-speed sustained axial climbing and descending flight, as well as flying in novel environmental conditions, such as forward flight in an extremely sheared velocity field. I use high-speed videography to capture detailed, three-dimensional kinematics, respirometry to obtain metabolic measurements, and aerodynamic models to estimate mechanical power output, in order to better understand different aspects of their flight performance. I interpret these findings both from an engineering context – how do they maintain control while descending directly into their wake, i.e. how do they deal with vortex ring state? – and a biological context – male Calypte anna ascend at 4-5 m/s, multiple times, in the course of their mating dive displays. Is this trivial or actually challenging, and what does this mean in terms of fitness, selection, and so on? Prior to my graduate work at UC Berkeley, I studied mathematics at New York University, doing research in the Applied Mathematics Lab.


  • Kim, E. J., Wolf, M., Ortega-Jimenez, V. M., Cheng, S. H., Dudley, R. (2014). Hovering performance of Anna’s hummingbirds (Calypte anna) in ground effect. J. R. Soc. Inter. 11 [doi: 10.1098/​rsif.2014.0505][link]
  • Jung, S., Kim, E., Shelley, M.J., and Zhang, J. (2007). Surface waves on a semi-toroidal water ring. Phys. Fluids. 19, 058105 [doi: 10.1063/1.2731808][arXiv]