Research Interests
I study the ecological and evolutionary processes responsible for divergence among populations and species. Specifically I am investigating at how natural selection and genetic drift contribute to divergence at different scales of space and time. I am interested in integrative research that bridges population genetics and phylogenetics, combining data from phylogeography, ecology, morphology, and behavior for a holistic description of divergence processes and speciation. I have mainly worked with birds, especially the Mexican jay (Aphelocoma ultramarina), but I am broadly interested in natural populations, specifically in the highlands of the western U.S. and Latin America.
Currently I am working with Lacey Knowles at the University of Michigan’s Museum of Zoology on methods for estimating species trees from multiple gene trees and Pleistocene speciation in montane grasshoppers of the diverse genus Melanoplus.
In my principal study site, the Sierra del Carmen of northern Coahuila, Mexico, I continue to work closely with biologists and wildlife managers of the Del Carmen Project, a conservation initiative of the Mexican cement company CEMEX. Northern Coahuila and the nearby Big Bend region of Texas are characterized by forested mountains (sky islands) isolated from one another by lowland desert. I am investigating adaptive divergence along elevation gradients and differentiation among sky islands in this region.Publications
McCormack, J.E. & T.B. Smith. 2008. Niche expansion leads to small-scale adaptive divergence along an elevation gradient in a medium-sized passerine bird. Proceedings of the Royal Society B: Biological Sciences. In press.
McCormack, J.E., A.T. Peterson, E. Bonaccorso & T.B. Smith. 2008. Speciation in the highlands of Mexico: genetic and phenotypic differentiation in the Mexican jay (Aphelocoma ultramarina). Molecular Ecology 17: 2505-2521.
Milá, B., J.E. McCormack, G. Castañeda, T.B. Smith, & R.K. Wayne. 2007. Recent postglacial range expansion drives the rapid diversification of a songbird lineage in the genus Junco. Proceedings of the Royal Society B: Biological Sciences 274: 2653-2660.
McCormack, J.E., P. Jablonski, & J.L. Brown. 2007. Producer-scrounger roles and the effect of dominance on preferential joining in a free-living group of Mexican jays (Aphelocoma ultramarina). Behaviour 144: 967-982.
McCormack, J.E., G. Castañeda-Guayasamin, & G. Levandoski. 2007. Sierra Santa Rosa: an oasis of bird diversity in arid northern Mexico. Ornitología Neotropical 18: 369-377.
McCormack, J.E., G. Castañeda Guayasamin, B. Milá, & F. Heredia-Pineda. 2005. Slate-throated redstarts (Myioborus miniatus) breeding in Maderas del Carmen, Coahuila, Mexico. Southwestern Naturalist 50: 501-503.
Avilés, L., J. McCormack, A. Cutter, & T. Bukowski. 2000. Precise, highly female-biased sex ratios in a social spider. Proceedings of the Royal Society B: Biological Sciences 267: 1445-1449.