- Scott R. McWilliams
- srmcwilliams@uri.edu
- University of Rhode Island
- Department of Natural Resources Science
- Coastal Institute in Kingston, #116
- 1 Greenhouse Road
- Kingston, RI 02881
- Voice:(401)-874-7531
- Fax:(401)-874-4561
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Assistant Professor of Wildlife Ecology |
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Ph.D., University of California at Davis, 1993 Dr. McWilliams is interested in the behavior, physiology, and ecology of individuals and how these characteristics determine population-level patterns of resource use, social organization, and interspecific interactions. He is particularly interested in the energetics, nutrition, and digestive physiology of threatened wild vertebrates, in the physiological and ecological implications of body size in herbivorous geese, and in how natural or anthropogenic environmental change impacts the ecology and physiology of wild vertebrates. Recent projects have addressed the life history and ecology of threatened salamanders, breeding and foraging ecology of arctic-nesting geese, and physiological and behavioral ecology of neotropical migrant songbirds. Research Areas Avian Herbivores and the Importance of Body Size Geese provide an interesting model for studying how avian herbivores circumvent the problem of combining the high energy demands of flight with the ecological limitations associated with eating leaves which are low in energy and nutrients and typically are high in fiber. Much theory focuses on the implications of body size for the physiological ecology of mammalian herbivores but it has yet to be adequately applied to avian herbivores. My previous work on avian herbivores has shown that highly selective feeding and microbial fermentation of dietary fiber are two ways geese escape some of the constraints associated with being a small avian herbivore. However, geese also show remarkable abilities to modulate digestive features in response to changes in diet quality and, as a result, they are able to maintain relatively high digestive efficiency on a wide range of diets. My current studies of geese focus on the allometrics of metabolic rate, gut capacity, digestive physiology, and foraging strategy within and between species. I am also conducting work in subarctic Canada on the nutritional and physiological ecology of gosling growth. The goal of the gosling growth study is to identify the effects of protein limitation and dietary fiber on growth rates of sympatric Canada and Snow geese. Information on growth rates and nitrogen requirements of Canada and Snow geese is particularly pertinent yet inadequate. Increased numbers of Snow geese have caused widespread destruction of their preferred salt-marsh plants. In response to this habitat destruction, snow geese are now nesting or raising broods in areas traditionally used primarily by Canada geese. The consequences of this habitat shift include increased competition between goslings of Canada and Snow geese for limited nutrients. Physiological Ecology of Songbirds Goals of my current research with songbirds include: (a) evaluate new nondestructive methods for measuring body composition dynamics in songbirds, (b) study the nutritional ecology of songbirds during migration, and (c) use stable isotopes to test contemporary hypotheses about the effect of diet quality and fasting on the metabolic routing of dietary nutrients in songbirds. Dynamics of body composition in small migratory songbirds-Understanding the dynamics of body composition in small migratory songbirds has fundamental and practical importance. The dynamics of body composition influences nutrient requirements which then interacts with resource availability to determine length of stopover at sites along the migration route, the pace of migration, and ultimately the success and survival of individuals. My students and I are currently conducting cross-validation studies that simultaneously use two different noninvasive techniques to independently estimate lean and fat mass of small songbirds during their migration. Such independent estimates of body components are a prerequisite for measuring dynamics of body composition in field-caught free-flying passerines. Nutritional ecology of birds during migration-Despite the obvious importance of stopover sites for recovery of stored energy and nutrients, the ecology and physiology of birds at stopover sites during migration is one of the least studied topics in bird migration. My students and I are currently studying how habitat quality and diet influence body condition and tempo of migration in small songbirds on Block Island, Rhode Island (an important stopover site along the northeast coast of North America). We are also using controlled studies in the laboratory to study nutrient preferences of songbirds and its effect on composition of endogenous reserves and subsequent migration performance in these birds. Use of stable isotopes to investigate the metabolic routing of dietary nutrients-Recently, animal ecologists interested in migratory birds have used stable isotope ratios to reconstruct diets and to trace movements between breeding and wintering areas. However, all such work relies on important untested assumptions about the effect of physiological processes on the stable isotope ratios. An important part of my research program involves testing some of these key assumptions while using stable isotopes to test hypotheses about the effect of metabolic routing of dietary nutrients on body composition dynamics in songbirds. Representative Publications: McWilliams, S.R. and W.H. Karasov. 2000. Digestive performance in migratory birds. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY, in press. McWilliams, S.R., E. Caviedes-Vidal, and W.H. Karasov. 1999. Digestive adjustments in cedar waxwings to high feeding rates. J. EXPERIMENTAL ZOOLOGY 283:394-407. McWilliams, S.R. 1999. Digestive strategies of avian herbivores. Pp. 2198-2207 in N.J. Adams and R.H. Slotow, eds. Proceedings of the XXII International Ornithological Congress, Durban, South Africa. McWilliams, S. R. and W. H. Karasov. 1998. Test of a digestion optimization model: effects of costs of feeding on digestive parameters. PHYSIOLOGICAL ZOOLOGY 71(2): 168-178. McWilliams, S. R. and D. G. Raveling. 1998. Habitat use and foraging behavior of cackling Canada and Ross' geese during spring: implications for the analysis of ecological determinants of goose social behavior. Pp. 167-178 in D.H. Rusch, M.D. Samuel, D.D. Humberg, and B.D. Sullivan, eds. BIOLOGY AND MANAGEMENT OF CANADA GEESE. Proceedings of the International Canada Goose Symposium, Milwaukee, Wisconsin. McWilliams, S. R. and W. H. Karasov. 1998. Do variable-reward feeding schedules affect digestive performance of migratory birds? OECOLOGIA 114:160-169. McWilliams, S. R., D. Afik, and S. Secor. 1997. Patterns and processes in the vertebrate digestive system: implications for the study of ecology and evolution. TRENDS IN ECOLOGY AND EVOLUTION 12:420-422. Recent Presentations: March 2000 - Invited symposium presentation at the annual meeting of the Society for Experimental Biology (Exeter, United Kingdom) "Digestive performance in migratory birds." August 1999 - 117th Annual meeting of the American Ornithologist's Union (Ithaca, N.Y.) "The cost of eating more: hyperphagia and digestive adjustments in migratory birds." March 1999 - Invited seminar at Dept. Wildlife Ecology, University of Maine (Orono, Maine) "Why avian herbivores are taxonomically rare but ecologically ubiquitous: a physiological and nutritional perspective." February 1999 - Invited Lecture Series on Rhode Island's Fauna, Flora, Geology, and Ecosystems (hosted by The Rhode Island Natural History Survey, University of Rhode Island) "Arctic-nesting geese in North America: tales of recovery and overabundance, and the contemporary destruction of arctic ecosystems." September 1998 - Fifth Annual meeting of The Wildlife Society (Buffalo, N.Y.) "Response of goslings to reduced forage quality." July 1998 - Foraging 98: Nervous Systems to Ecosystems (Santa Cruz, CA) "Physiological mechanisms of foraging: testing an optimal digestion model." People involved with my program Megan Whitman, MSc student Barbara Wilson, PhD student Many undergraduates conducting independent research projects or internships Membership:
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