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Michael T. Hallworth

Past Fellow

Research Interests

I am an ecologist that takes a full annual cycle approach to understand the interplay between the environment and population demography. To do this, it’s imperative to integrate movement at multiple spatial scales – from fine scale habitat selection of individuals to intercontinental migrations of populations. Identifying how different phases of the annual cycle interact to shape individual, population- and community dynamics, is essential to understand how they respond to global change. The overarching goals of my research program included 1) reveal the mechanisms that drive behavior, life-history and demographics of wildlife populations, 2) identify where migratory individuals and populations are throughout the year to better inform conservation and 3) determine when and where wildlife populations are limited.


Hallworth, M. T., P. P. Marra, K. E. McFarland, S. Zahendra and C. E. Studds. 2018. Tracking dragons: Stable-isotopes reveal the annual cycle of a long-distance migratory insect. Biology Letters. 20180741 *Cover article. 
Cohen, E. B., C. R. Rushing, F. R. Moore, M. T. Hallworth, J. A. Hostetler, M. Gutierrez Ramirez and P. P. Marra. 2018. Spatial and temporal en route migratory connectivity of three Nearctic-Neotropical species through the Gulf of Mexico region. Ecography. 42, 1-12.
Lisovski, S., H. Schmaljohann, E. S. Bridge, S. Bauer, A. Farnsworth , S. A. Gauthreaux, Jr., S. Hahn, M. T. Hallworth, C. M. Hewson, J. F. Kelly, F. Liechti, P. P. Marra, E. Rakhimberdiev, J. D. Ross, N. E. Seavy, M. D. Sumner, C. M. Taylor, D. W. Winkler, S. J. Wotherspoon, and M. B. Wunder. Inherent limits of light-level geolocation may lead to over-interpretations (Comment on Streby et al. (2015) Tornadic Storm Avoidance Behavior in Breeding Songbirds. Curr. Biol. 25, R98-R102.). 2018. Current Biology. 28:3. R99-R100.
Cohen, E. B., J. Hostetler, M. T. Hallworth, C. Rushing, T. S. Sillett and P. P. Marra. 2018. A quantitative definition for the strength of migratory connectivity. Methods in Ecology and Evolution. 9:3. 513-524.
Reitsma, L. R., J. J. Jukosky, A. J. Kimiatek, M. L. Goodnow, and M. T. Hallworth. 2018. Extra-pair paternity in a long-distance migratory songbird beyond neighbors’ borders and across male age classes. Canadian Journal of Zoology. 96:1. 49-54.
Haché, S. E.M. Bayne, M.-A. Villard, H. Proctor, C.S. Davis, D. Stralberg, E. Vasi, A. Grossi, J.C. Gorrell, J.K. Janes, M.T. Hallworth, K.R. Foster and R. Krikun. 2017. Phylogeography of a migratory songbird across its Canadian breeding range: implications for conservation units. Ecology and Evolution. 7:6078–6088.
Cooper, N. W., M. T. Hallworth and P. P. Marra. 2017. Light-level geolocation reveals wintering distribution, migration routes, and primary stopover locations of an endangered long-distance migratory songbird. Journal of Avian Biology. 48:2. 209-219.  *Cover article.
Hallworth, M. T. and P. P. Marra. 2015. Miniaturized GPS Tags Identify Non-breeding territories of a small breeding migratory songbird. Scientific Reports. 5:11069. doi:10.1038/srep11069.
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Ph.D.: Environmental Science and Public Policy, George Mason University, Fairfax, VA.
M.S.: Biology, Plymouth State University, 2007, Plymouth, N.H.
B.S.: Biology, Plymouth State University, 2004, Plymouth, N.H.