Since 2008, our lab has been working on migration patterns and population dynamics of monarch butterflies. We primarily use stable isotopes in wing chitin to estimate the natal origin of individuals captured throughout the range and over multiple seasons. Our goal with this work is to describe broad-scale connectivity patterns across the eastern breeding range and then integrate this information into year-round predictive population models to understand what limits and regulates migratory monarch butterflies. We have also been involved in a collaborative project to understand the proximate causes of migratory behaviour.
Flockhart, DTT, Brower, LP, Ramirez, MI, Hobson, KA, Wassenaar, LI, Altizer, S & Norris, DR. Regional climate on the breeding grounds predicts variation in the natal origin of monarch butterflies overwintering in Mexico over 38 years. In press: Global Change Biology
Flockhart, DTT, Kyser, TK, Chipley, D, Miller, N & Norris, DR. 2015. Applying strontium isotopes (87Sr/86Sr) for tracking wildlife: experimental evidence shows no fractionation between soil, plants, and herbivores. Isotopes in Environmental & Health Studies 51(3): 372-381.
Flockhart, DTT, Pichancourt, JB, Norris, DR & Martin TG. 2015. Unraveling the annual cycle in a migratory animal: breeding-season habitat loss drives declines of monarch butterflies. Journal of Animal Ecology 84: 155-165.
Flockhart, DTT, Wassenaar, LI, Hobson, KA, Martin, TG, Wunder, MB & Norris, DR. 2013. Tracking multi-generational colonization of the breeding grounds by monarch butterflies in eastern North America. Proceedings of the Royal Society, London: Biological Sciences 280 (1768).
Mouritsen, H, Derbyshire, R, Stakkeicken, J, Frost, B, Mouritsen, O & Norris, DR. 2013. An experimental displacement and over 50 years of tagged-recoveries show that monarch butterflies are not true navigators. Proceedings of the National Academy of Sciences, USA 110(18): 7348-7353.
Hanley, D, Miller, N, Flockhart, DTT & Norris, DR. 2013. Forewing pigmentation predicts migration distance in wild-caught migratory monarch butterflies. Behavioural Ecology 24: 1108-1113.
Miller, NG, Wassenaar, LI, Hobson, KA & Norris, DR. 2012. Migratory connectivity in the Monarch butterfly: patterns of spring re-colonization in eastern North America. Public Library of Science, One 3: e39891.
Flockhart, DTT, Martin, TM, & Norris, DR. 2012. Experimental examination of intraspecific density-dependent competition during the breeding period in Monarch butterflies (Danaus plexippus). Public Library of Science, One 7(9): e45080.
Miller, NG, Wassenaar, LI, Hobson, KA & Norris, DR. 2011. Monarch butterflies cross the Appalachians from the west to re-colonize the North American east coast. Biology Letters 7: 43-46.