Mark has been teaching in the Environmental Studies Program at Prescott College since 1988. His courses offer a strong foundation in the biological sciences and combine theory with an experiential emphasis. This is especially the case in his field courses in Mexico, Costa Rica, and East Africa, but his on-campus courses also include numerous field trips and, in many instances, hands-on laboratory exercises. In all his teaching, he strives to weave together an understanding of ecological principles with evolutionary theory so that students can cultivate an appreciation for the origin and maintenance of biological diversity.
PhD, Ecology and Evolution, State University of New York at Stony Brook
BS, Biology, State University of New York College at Brockport, cum laude
Clark, E. W., A. B. Fleishman and M. F. Riegner. 2015. Diversity, abundance and nesting phenology of the wading birds of Bahia Kino, Sonora, Mexico. Waterbirds 38(4): 355-363.
Riegner, M. F. 2014. The phenomenology of betweenness: Encountering nature's wholeness. Environmental and Architectural Phenomenology 25(3): 28-32.
Riegner, M. F. 2013. Ancestor of the new archetypal biology: Goethe's dynamic typology as a model for contemporary evolutionary developmental biology. Studies in History and Philosophy of Biological and Biomedical Sciences 44: 735-744.
Riegner, M. F. 2008. Parallel evolution of plumage pattern and coloration in birds: Implications for defining avian morphospace. Condor 110: 599-614.
Riegner, M. 1998. Horns, hooves, spots, and stripes: Form and pattern in mammals. In Goethe's way of science: A phenomenology of nature. D. Seamon and A. Zajonc, Editors. SUNY Press, Albany, New York, pp. 177-212. [and translated into Norwegian in 2010 for The Ariadne Annual.]
Riegner, M., and J. Wilkes. 1998. Flowforms and the language of water. In Goethe's way of science: A phenomenology of nature. D. Seamon and A. Zajonc, Editors. SUNY Press, Albany, New York, pp. 233-252.
Riegner, M. 1993. Toward a holistic understanding of place: Reading a landscape through its flora and fauna. In Dwelling, seeing, and designing: Toward a phenomenological ecology. D. Seamon, Editor. SUNY Press, Albany, New York, pp. 181-215.
Fleischner, T., and M. Riegner. 1993. Winter birds of Bahia Kino, central Gulf of California coast, Sonora, Mexico. Ecologica 3 (1): 29-34.
Riegner, M., and L. Niemeyer (photographer). 1993. Long-legged wading birds of the North American wetlands. Stackpole Books, Harrisburg, Pennsylvania.
Riegner, M. 1992. Look-alike birds from distant lands: A consideration of similarities in unrelated birds. Birder's World 6(3): 17-21.
Mark's current research focuses on questions concerning the diversity of avian plumage patterns. Why do similar plumage patterns repeatedly evolve in distantly related lineages while strikingly different plumage configurations may be exhibited in closely related taxa? Why do some species have streaks while others have bars? Is there a relationship between plumage pattern and morphology? Accordingly, he has identified an empirically derived plumage pattern trajectory that covaries with body size and morphology across the Class Aves (see Riegner, 2008). Furthermore, the trajectory is recursive at various taxonomic levels, such as within genera and within families, and thus serves as an indicator of parallel evolution. The recursive nature of the trajectory, in which morphological and chromatic elements recur in modified configurations, has perhaps contributed to an underestimate of parallel evolution in birds.
Mark's other projects focus on the intersection of morphology, development, evolution, behavior, and ecology. He is currently investigating the relationship between various skeletal features of herons (based on measurements of museum specimens) and correlating these with the development of prehensility in nestlings. Basically, smaller species (such as the Green Heron) tend to accelerate the development of the grasping reflex but then exhibit this behavioral ability to a high degree throughout their adult lives by foraging mainly by perching on branches, roots, or reeds. Larger species (such as the Great Blue Heron) delay development of the grasping reflex and then develop more specialized limbs for walking on flat substrates. In another project, in collaboration, he is studying how various non-feathered structures on a bird's head (casque, wattles, knob, etc.) affect aerodynamics, with a potentially greater cost the smaller the size of the bird.
In addition, Mark is interested in exploring dynamic ways of thinking about understanding the origin, diversity, constraints, and evolution of biological form. This has led him to research key figures in the history and philosophy of the biological sciences (see Riegner, 2013). He also continues field research on the ecology of wading birds (see Clark, Fleishman and Riegner, 2015), as well as morphological studies of this group. Based on a literature review and recent (2017) field experience in the Brazilian Pantanal, he is also studying the "morphodynamic convergence" between primates and parrots, and has identified some previously reported and some new parallels in behavior, development, phylogeny, and even morphology between the two groups.
"Feathers and Beaks, Bars and Streaks: Form and Pattern in Birds;" Natural History Institute, Prescott, Arizona; April 2018.
"Parallel Evolution of Plumage Pattern and Coloration in Birds: Implications for Defining Avian Morphospace;" Department of Biology and Philosophy, Charles University, Prague, Czech Republic; October 2017.
"Exploring the Occupation of Morphospace Based on Goethe's Dynamic Typology: Insights into the Morphology, Ecology, and Behavior of Birds;" Evolving Morphology: 200 Years of Goethe's Morphological Notebooks, Goetheanum, Dornach, Switzerland; October 2017.
"Biological Evolution and Natural History: An Intertwined Path;" Highlands Center for Natural History, Prescott, Arizona; September 2017.
"Morphological Trade-offs and Recursive Plumage Patterns as Indicators of Integrated Evolutionary Dynamics in the Ardeidae;" Ecology Department, Federal University of Mato Grosso do Sul, Brazil; August 2017.
"Morphological Trade-offs and Recursive Plumage Patterns as Indicators of Integrated Evolutionary Dynamics in the Ardeidae;" Scientific session, Waterbird Society Conference, New Bern, North Carolina; September 2016.
"Marvelous Mammals of the Central Arizona Highlands;" Highlands Center for Natural History, Prescott, Arizona; February 2016.
"Behavior and Conservation of Herons around the World;" Prescott Audubon Society; March 2015.
"Feathers and Beaks, Bars and Streaks: Form and Pattern in Birds;" Bird Conservation Society of Thailand, Bangkok, Thailand; June 2014.
"Goethe's Dynamic Vision in Science and Art;" Marshall-LeKae Art Gallery, Scottsdale, Arizona; April 2014.
“Mammals of the Central Arizona Highlands;” Highlands Center for Natural History, Prescott, Arizona; February 2014.
"Correlated Evolution of Color Pattern and Morphology in Birds and in Mammals;" Environmental Studies Colloquium Series, Prescott College; November 2010.
"Occurrence of Nonfeathered Avian Integumentary Outgrowths: Evidence for Parallel Evolution;" Poster presentation, American Ornithologists' Union, San Diego, CA; February 2010.
"Herons of the Salton Sea;" Presentation at the Salton Sea International Birding Festival, Imperial, CA; February 2010.
"Parallel Evolution of Plumage Pattern and Coloration in Birds: Implications for Defining Avian Morphospace;" Scientific session, American Ornithologists' Union, University of Wyoming, Laramie; August 2007.
“Plumage Pattern and Coloration as Correlates of Avian Morphology;” Scientific session, American Ornithologists’ Union, UC Santa Barbara; August 2005.
“Feathers and Beaks, Bars and Streaks: Form and Pattern in Birds;” Environmental Studies Colloquium Series, Prescott College; March 2005.
Awards, Grants & Honors
2011 Harry R. Painton Award of the Cooper Ornithological Society, for his paper “Parallel evolution of plumage pattern and coloration in birds: implications for defining avian morphospace” selected as the best paper published in The Condor over the last four years.
The published article by Clark, Fleishman and Riegner (2015) is highlighted on Waterbirds Journal Facebook page and as "Editor's Choice" on the Waterbirds Society website.
Coverage in News & Media
Research based on the paper by Clark, Fleishman, and Riegner (2015) was covered on Discovery News, with a photo spread and interview.
Previous to the above coverage on Discovery News, Mark was invited to comment on an article about the discovery of the first physical evidence for dinosaur courtship behavior.