McWilliams, Scott R.
- Postdoctoral Fellow, University of Wisconsin at Madison (Wildlife Ecology)
- Ph.D., University of California at Davis (Wildlife & Conservation Biology)
- M.Sc., Iowa State University (Animal Ecology)
- B.A., Hiram College (Biology, Psychology, Environmental Studies)
- Senior Colloquium (NRS 480)
- Wildlife Field Techniques (NRS 309)
- Physiological Ecology (NRS 538)
- Advanced Ecology (EVS 550)
Dr. McWilliams’ research focuses on 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, habitat selection of ruffed grouse in relation to forest management, physiological ecology of gosling growth in arctic ecosystems, and physiological and behavioral ecology of neotropical migrant songbirds.
Research and Employment Opportunities
We regularly offer excellent opportunities for scientists at all levels to join our research team at University of Rhode Island. Postdoctoral and graduate research opportunities are advertised widely and this page lists current openings. We encourage interested applicants to contact us about future opportunities that have not yet been advertised.
At least two positions should be available starting winter 2012 pending grant awards. Contact Dr. McWilliams directly about these opportunities.
Graduate Research Assistantships:
Full-time research/teaching assistantships are usually available each Fall semester. These opportunities are usually advertised on the TWS listserv, the ESA listserv, the on-line Ornithological Newsletter, and other places. There are also links at the NRS homepage that provide further information about the Graduate Program at URI. All graduate students in our research team are trained as part of one of two graduate programs: Ecology & Ecosystem Sciences, or Integrative & Evolutionary Biology.
Research Interests and Current Projects
My research primarily focuses on the nutritional and physiological ecology of wild vertebrates, with an emphasis on species of conservation interest. Using a combination of field and laboratory approaches, I have studied a diversity of vertebrates including carnivorous salamanders, herbivorous waterfowl and grouse, as well as insectivorous, frugivorous, and granivorous passerine birds. Three common themes are evident in my research: (1) I regularly use comparisons between species to reveal broadscale patterns in nutritional and physiological ecology, (2) the research questions that I investigate focus on aspects of the physiology and nutrition of wild vertebrates that are relevant to the animal’s ecology, and (3) I conduct integrative studies of a given organism. For example, I combine work on metabolic physiology, membrane transport of nutrients, digestive physiology, nutritional requirements, feeding behavior, ecological energetics, and constraints (e.g. morphological, developmental, physiological) on prey and predator form and function. To accomplish such an integrative research program requires successful collaboration. Below I provide examples of some current research projects that demonstrate these common themes.
Use of Stable Isotopes in Studies of the Nutritional and Physiological Ecology of Migratory Birds
Plant physiological ecologists have used natural variation in stable isotope ratios to study photosynthesis, water balance, and nitrogen metabolism in plants. In contrast, animal physiological ecologists have made much less use of naturally occurring stable isotopes in their research despite its great potential. 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, most of the significant advances in the near future will come only after we have a better understanding of the physiological processes that influence stable isotope signatures in free-living animals.
A primary focus of my NSF CAREER grant is to use stable isotopes to study metabolic routing of dietary nutrients in birds. For example, we have used stable isotopes of carbon and nitrogen to detect protein deficiency in growing goslings. Theoretically, animals deficient in dietary protein must recycle endogenous nitrogen thereby enriching the N isotope ratio. Using controlled laboratory studies, we compared isotope ratios of Canada and Snow goose goslings raised on diets with either deficient or adequate protein levels, and found they indicated protein deficiency in growing goslings. In addition, David Podlesak (PhD 2004) and I have recently used stable isotopes to quantify how certain dietary nutrients are metabolically routed to certain tissues during fasting and flying in migratory warblers. The advantage of using naturally occurring stable isotopes for this work is that the results can be easily applied to free-living birds. For example, we have conducted field studies of diet switching in free-living songbirds at migration stopover sites by comparing patterns of stable isotopes in selected wild fruits and insects, and in the breath, blood, feces, and feathers of the birds. Current projects in which we use stable isotopes include further studies of metabolic routing of dietary nutrients in passerine birds, habitat use of goslings in Hudson Bay (Canada), energetics of passerine birds during long-distance flight, and estimating body composition of live songbirds at stopover sites during their migration.
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 physiological limitations associated with eating leaves which are low in energy and nutrients and 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. Geese are an excellent group in which to study such issues because species such as the Canada goose vary 7-fold in body size. My previous work on avian herbivores has shown that highly selective feeding is one way 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 growth in geese in relation to projected climate change.
Another current project (ongoing since 1999) focuses on habitat use and population dynamics of Ruffed Grouse in southern New England. This is a cooperative project with Brian Tefft, the state wildlife biologist with Dept. Environmental Management in Rhode Island. The primary goal of the proposed research is to assess how habitat quality and forest management practices affect home range and survival of grouse in southern New England, and to establish the efficacy of relocating grouse to enhance grouse populations in RI. Starting in fall 2005, this project expanded so that we are now assessing how forest management that produces early successional forest affects the southern New England bird community, in general, and Ruffed Grouse, in particular.
Incubation patterns in relation to disturbance of Piping Plovers at Cape Cod National Seashore
During incubation, birds must balance the need to attend the nest so that proper embryological development occurs with the need to leave the nest to forage and satisfy their energetic requirements. However, each time a bird leaves its nest the eggs may change temperature and the location of the nest may be detected by a predator. Since 2002, Eric Schneider (MSc candidate) and I have been investigating nest attendance patterns of the endangered Piping Plover at Cape Cod National Seashore (MA). The primary goal of the project is to use inexpensive iButton ® data loggers and thermocouples in plover nests to determine how human disturbance or predators affect nest attendance patterns of the plovers.
Contemporary Studies of the Nutritional and Physiological Ecology of Migratory Songbirds
(1) Digestive Physiology, Digestive Constraints, and Its Ecological Implications
Birds may often experience short-term changes in food quantity and quality. For example, frugivorous birds during migration may one day encounter preferred fruits that are ubiquitous allowing relatively constant food intake, whereas the next day their preferred fruits may be patchily-distributed and require much travel time between patches. In such situations, a bird’s daily pattern of food intake may differ from day to day. Theoretical optimality models make explicit predictions about how an animal’s digestive features should respond to short-term changes in food quantity and quality although prior to my work there had been no such tests of the models for changes in food intake. To test the predictions of the theoretical optimality models, we manipulated foraging costs in insectivorous warblers and frugivorous waxwings and measured whole-animal features such as digestive efficiency and passage rates using radioactive isotopes while also measuring suborganismal features that determine whole-animal performance such as tissue-specific levels of digestive enzymes and active and passive transport of specific nutrients across the intestinal membrane. All the theoretical predictions were rejected. Warblers and waxwings did not increase retention time and digestive efficiency in situations with higher foraging costs as predicted by the model, suggesting that these digestive parameters may be regulated to minimize feeding time rather than maximize rate of net energy gain. We have recently summarized the ecological circumstances that lead to digestive constraints in both birds during migration (McWilliams and Karasov 2005) and birds and mammals, in general (Karasov and McWilliams 2005).
(2) Diet Preferences for Specific Nutrients (e.g. Fatty Acids) and its Energetic Consequences
The nutrient requirements of an animal depend on its physiologically state. For example, during periods of fat storage (e.g. during migration or in the cold), birds store impressive amounts of fats comprised mostly of longchain unsaturated fatty acids. Theoretically, selectively feeding on long-chain unsaturated fatty acids may be advantageous because such fatty acids may be absorbed and/or metabolized more efficiently than saturated fats into a bird’s fat depots. We tested this hypothesis by offering warblers and vireos in different physiological states choices between diets that varied only in their fatty acid composition. We found that (1) birds prefered diets with mostly long-chain unsaturated fatty acids especially during energy-demanding periods of the annual cycle, and (2) both diet composition and selective metabolism were important in determining the fatty acid composition of depot fat in migratory birds. Barbara Pierce (PhD, 2003) and I recently conducted the first studies that demonstrate that birds with certain ratios of unsaturated to saturated fatty acids in their fat reserves have greater aerobic capacity while exercising. How migrating birds acquire preferred fatty acids in the wild is not well understood, but our recent work suggests that it has important implications for the energetics of migration. Current projects focus on how dietary fatty acids and antioxidants affect metabolism of fatty acids and exercise performance in birds during flight (in the windtunnel at the Max Planck Institute for Ornithology in Germany).
(3) Changes in Body Composition of Birds during their Migration
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. Of the few studies reporting utilization of fat and protein reserves in migratory passerines, most use regressions of fat mass and body mass from birds sampled during migration to quantify protein reserves. Unfortunately, this method has a poor theoretical rationale and methodological shortcomings. Megan Whitman (MSc, 2002) and I completed the first cross-validation study that simultaneously uses two different nondestructive techniques (TOtal Body Electrical Conductivity (TOBEC) and isotope dilution) to independently estimate lean and fat mass of small songbirds during their migration. Using these techniques, we can estimate lean mass with precision of ca. 0.5 g and fat mass with precision of
(4) Phenotypic flexibility in physiological traits
The capacity of many physiological systems, including that of the digestive system, is matched to the prevailing demand but can be modulated in response to changes in demand. Such phenotypic flexibility in physiological traits may itself be a critical component of the adaptive repertoire of animals that may influence diet diversity, niche width, feeding rate, and thus the acquisition of energy and essential nutrients. However, the key organs of a physiological system are not exactly matched to the prevailing demand, but instead they provide some limited excess capacity. This so-called “spare capacity” is ecologically important because it defines the limits of shortterm response in animals. Because changes in feeding rate and diet are common in migratory birds, understanding the extent of spare capacity in their digestive system provides insights into when digestion may constrain diet choice and feeding rate. We have found that phenotypic flexibility in the digestive system of migratory birds is pervasive and has important ecological significance. Current projects focus on how the flexibility and capacity of the avian digestive system varies across taxa and how it is related to the phylogeny, ecology, and life history of birds.
Implications of the research for Wildlife Management and Ecology (a few examples)
My research on geese during spring has provided managers in California with information on the habitats and plant species selected by the Cackling and Ross geese, carrying capacity of specific habitat types, nutritional requirements of the geese, the effects of goose grazing on crop yield, and the sensitivity of geese to disturbance. This information is currently being used by state biologists who are purchasing and managing habitat particularly for Cackling geese because of their low population size. The goal of our gosling growth study is to identify the effects of protein limitation and dietary fiber on growth rates of sympatric arctic-nesting 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. We tested the hypothesis that interspecific differences in nutritional requirements of goslings allow Snow goose goslings to survive better than Canada goose goslings in arctic and sub-arctic habitats that are degraded. However, contrary to the predictions of the hypothesis, Canada goose goslings had lower protein requirements and tolerated higher fiber foods than Snow goose goslings. Thus, in the degraded, overgrazed habitats now common along Hudson and James Bay, Canada, interspecific differences in nutritional requirements of goslings can not explain why populations of Snow geese are increasing while populations of Canada geese are declining. Finally, my research on songbirds provides information about how much these migratory passerines eat and digest during migration, their dietary preferences at stopover sites during migration, and the importance of physiological constraints in limiting rate of fattening. As part of this research, we are using non-lethal methods such as deuterium and total electrical body conductivity (TOBEC) to determine how habitat quality influences body composition of small passerine birds during migration. These results and new techniques can be used, for example, in managing populations of threatened species of neotropical migrants.
- Skrip, M., S.R. McWilliams. 2016. Oxidative balance in birds: an atoms-to-organisms-to-ecology primer for ornithologists. J. Field Ornithology, in press.
- Beuth, J.M., P.W.C. Paton, J.E. Osenkowski, S.R. McWilliams. 2016. Validating the deuterium dilution method to assess body composition of Common Eider. WILDLIFE SOCIETY BULLETIN, in press.
- Beuth, J.M., P.W.C. Paton, J.E. Osenkowski, S.R. McWilliams. 2016. Body composition dynamics of male and female Common Eider during winter: an application of the deuterium dilution method. WILDLIFE SOCIETY BULLETIN, in press.
- Smith, A.D., S.R. McWilliams. 2016. Autumn Coastal Bat Migration Relates to Atmospheric Conditions: Implications for Wind Energy Development. J. MAMMALOGY, in press.
- McWilliams, S.R., E. Adkins-Regan, C. Vleck. 2016. How birds work: avian physiology within an ecological context. Chapter 7 in Cornell Ornithology Laboratory, Handbook of Bird Biology. Cornell University Press, Ithaca
- Masse, R.J., B.C. Tefft, and S.R. McWilliams. 2015. Higher bird abundance and diversity where America Woodcock sing: fringe benefits of managing forests for Woodcock. J. WILDLIFE MANAGEMENT 79:1378-1384. [PDF Copy]
- Coluccy, J.M., M.V. Castelli, P.M. Castelli, J.W. Simpson, S.R. McWilliams, L. Armstrong. 2015. True metabolizable energy of American Black Duck foods. J. WILDLIFE MANAGEMENT 79(2):344-348. [PDF Copy]
- Richman, S.E., J.O. Leafloor, W.H. Karasov, and S.R. McWilliams. 2015. Ecological implications of reduced forage quality on growth and survival of sympatric geese. JOURNAL OF ANIMAL ECOLOGY 84:284-298. [PDF Copy]
- Skrip, M., U. Bauchinger, W. Goymann, L. Fusani, S.R. McWilliams. 2015. Access to water affects the condition dependency of nocturnal restlessness in Garden Warblers on a Mediterranean island stopover. JOURNAL OF ORNITHOLOGY, in press. [PDF Copy]
- Smith, A.D., S.R. McWilliams, K.J. Winiarski, C.L. Trocki, B. Harris, J.E. Osenkowski, and P.W.C. Paton. 2015. Using land-based surveys to assess sea duck abundance and behavior in nearshore waters of southern New England, USA. WATERBIRDS 38(3), in press. [PDF Copy]
- Skrip, M., U. Bauchinger, W. Goymann, L. Fusani, M. Cardinale, R. Alan, S.R. McWilliams. 2015. Migrating songbirds on stopover prepare for, and recover from, oxidative challenges posed by long-distance flight. ECOLOGY AND EVOLUTION 5(15):3198-3209. [PDF Copy]
- Williams, C. K., B.D. Dugger, M.G. Brasher, J.M. Coluccy, D.M. Cramer, J.M. Eadie, M.J. Gray, H.M. Hagy, M. Livolsi, S.R. McWilliams, M. Petrie, G.J. Soulliere, J.M. Tirpak, and E.B. Webb. Estimating habitat carrying capacity for migrating and wintering waterfowl: considerations, pitfalls and improvements. Wildfowl, in press (Special Issue 4):407-435. [PDF Copy]
- Smith, A.D., S.R. McWilliams. 2014. What to do when stopping over: behavioral decisions of a migrating songbird during stopover are dictated by initial change in their body condition and mediated by key environmental conditions. BEHAVIORAL ECOLOGY, 25:1423-1435. [PDF Copy]
- Pierce, B.J., S.R. McWilliams. 2014. The fat of the matter: how dietary fatty acids can affect exercise performance. INTEGRATIVE AND COMPARATIVE BIOLOGY, in press 54:903-912. [PDF Copy]
- Ladin, Z.S., C.K. Williams, P.M. Castelli, K.J. Winiarski, J. Osenkowski, S.R. McWilliams. 2014. Regional and intraseasonal variation in diet of wintering and staging Atlantic Brant. JOURNAL OF WILDLIFE MANAGEMENT, in press 78:1206-1215. [PDF Copy].
- Coon, C.A.C, A.J. Brace, S.R. McWilliams, M.D. McCue, L.B. Martin. 2014. Introduced and native congeners use different resource allocation strategies to maintain performance during infection. PHYSIOLOGICAL AND BIOCHEMICAL ZOOLOGY, in press 87:559-567. [PDF Copy].
- Masse, R.J., B. Tefft, S.R. McWilliams. 2014. Multiscale habitat use by a forest-dwelling shorebird, the American woodcock: implications for forest management in southern New England, USA. FOREST ECOLOGY AND MANAGEMENT 325:37-48 [PDF Copy].
- Smith, A.D., P.W. Paton, S. R. McWilliams. 2014. Using nocturnal flight calls to assess the fall migration of warblers and sparrows along a coastal ecological barrier. PLoS ONE 9(3): e92218 [PDF Copy].
- Richman, S.E., J.O. Leafloor, W.H. Karasov, and S.R. McWilliams. 2014. Ecological implications of reduced forage quality on growth and survival of sympatric geese. JOURNAL OF ANIMAL ECOLOGY, in press 84:284-298 [PDF Copy].
- McWilliams, S.R. and W.H. Karasov. 2014. Spare capacity and phenotypic flexibility in the digestive system of a migratory bird: defining the limits of animal design. PROC R SOC B 281:1-9 [PDF Copy].
- Buffum, W., C. Modisette, S.R. McWilliams. 2014. Encouraging family forest owners to create early successional wildlife habitat in Southern New England. PLoS One 9(2): e89972. doi:10.1371/journal.pone.0089972 [PDF Copy]
- Winiarski, K. D.L. Miller, P.W.C. Paton, S.R. McWilliams. 2014. A spatial conservation prioritization approach for protecting marine birds given proposed offshore wind energy development. BIOLOGICAL CONSERVATION 169:79-88 [PDF Copy].
- Winiarski, K., M.L. Burt, E.A. Rexstad, D.W. Miller, C.L. Trocki, P.W.C. Paton, S.R. McWilliams. 2014. Integrating aerial and ship surveys of marine birds into a combined density surface model: A case study of wintering Common Loons. Condor: Ornithological Applications 116:149-161 [PDF Copy].
- Loring, P. P.W.C. Paton, J. Osenkowski, S. Gilliland, J.P. Savard, S.R. McWilliams. 2014. Habitat use and selection of Black Scoters in southern New England and siting of offshore wind energy facilities. JOURNAL OF WILDLIFE MANAGEMENT 78(4):645-656 [PDF Copy].
- Smith, A., S. R. McWilliams. 2014. Fruit removal rate depends on neighborhood fruit density, frugivore abundance, and spatial context. OECOLOGIA 174:931-942 [PDF Copy].
- Hall, Z., U. Bauchinger, A. Gerson, E. Price, L. Langlois, M. Boyles, B. Pierce, S. McWilliams, S. MacDougall-Shackleton. 2013. Site-specific regulation of adult neurogenesis by dietary fatty acid content, vitamin E, and flight exercise in European starlings. EUROPEAN JOURNAL OF NEUROSCIENCE 2013:1-8 [PDF Copy].
- Winiarski, K., D.W. Miller, P.W.C. Paton, S. R. McWilliams. 2013. Spatially explicit model of wintering common loons: conservation implications. MEPS 492:273-283 (doi: 10.3354/meps10492) [PDF Copy].
- Masse, R., B.C. Tefft, J.A. Amador, S.R. McWilliams. 2013. Why woodcock commute: testing the foraging-benefit and predation-risk hypotheses. BEHAVIORAL ECOLOGY 24:1348-1355 [PDF Copy].
- Ben-Hamo, M., M.D. McCue, I. Khozin-Goldberg, S. R. McWilliams, B. Pinshow. 2013. Ambient temperature and nutritional stress influence the fatty acid composition of polar and neutral lipids in Japanese Quail (Coturnix japonica) tissues. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY 166A:244-250 [PDF Copy]
- Alan, R., S.R. McWilliams, K.J. McGraw. 2013. The importance of antioxidants for avian fruit selection during autumn migration. WILSON JOURNAL OF ORNITHOLOGY 125:513-525 [PDF Copy].
- Loring, P., P.W.C. Paton, R.A. McKinney, C.A. Oviatt, and S.R. McWilliams. 2013. Densities of wintering scoters in relation to benthic prey assemblages in a North Atlantic estuary. WATERBIRDS 36:144-155 [PDF Copy].
- McWilliams, S.R. and M. Whitman. 2013. Non-destructive techniques to assess body composition of birds: A review and validation study. JOURNAL OF ORNITHOLOGY 154:597-618 [PDF Copy].
- Alan, R.R. and S.R. McWilliams. 2013. Oxidative stress, circulating antioxidants, and dietary preferences in songbirds. COMPARATIVE PHYSIOLOGY AND BIOCHEMISTRY B 164:185-193 [PDF Copy].
- Bolser, J.A., A.D. Smith, R.R. Alan, L. Li, N.P. Seeram, S.R. McWilliams. 2013. Birds select fruits with more antioxidants during autumn migration. WILSON JOURNAL OF ORNITHOLOGY 125:97-108 [PDF Copy].
- McKinney, R.A. and S.R. McWilliams. 2012. Energy-based carrying capacities of Bufflehead Bucephala albeola wintering habitats. The Open Ornithology Journal 5:5-17 [PDF Copy].
- Cohen, A., L.B. Martin, J.C. Wingfield, S.R. McWilliams, J.A. Dunne. 2012. Physiological regulatory networks: ecological roles and evolutionary constraints. Trends in Ecology and Evolution 27(8):428-435 [PDF Copy].
- Bauchinger, U. and S.R. McWilliams. 2012. Tissue-specific mass changes during fasting: the protein turnover hypothesis. Chapter 12, pp. 193-206, in M. McCue (ed) The Comparative Physiology of Fasting and Starvation. Springer-Verlag, Berlin [PDF Copy].
- Winiarski, K., S.R. McWilliams, R. Rockwell. 2012. Rapid environmental degradation in a subarctic ecosystem influences resource use of a keystone avian herbivore. JOURNAL OF ANIMAL ECOLOGY 81:1132-1142 [PDF Copy].
- Nebel, S., U. Bauchinger, D.M. Buehler, L.A. Langlois, M. Boyles, A.R. Gerson, E.R. Price, S.R. McWilliams, and C.G. Guglielmo. 2012. Constitutive immune function in European starlings Sturnus vulgaris is decreased in response to endurance flight in a wind tunnel. JOURNAL OF EXPERIMENTAL BIOLOGY, in press. [PDF Copy]
- Mizrahy, O., U. Bauchinger, S. Aamidor, S.R. McWilliams, B. Pinshow. 2012. Water availability affects tissue renewal in migratory blackcaps during stopover. INTEGRATIVE AND COMPARATIVE BIOLOGY, in press.[PDF Copy]
- Munoz-Garcia, A., S. Aamidor, M.D. McCue, S.R. McWilliams, B. Pinshow. 2012. Allocation of endogenous and dietary protein in the reconstitution of the gastrointestinal tract in migratory blackcaps at stopover sites. JOURNAL OF EXPERIMENTAL BIOLOGY, in press. [PDF Copy]
- McWilliams, S.R. 2011. Ecology of Vertebrate Nutrition, 2nd edition. ENCYCLOPEDIA OF LIFE SCIENCES, John Wiley & Sons, Ltd, United Kingdom. DOI: 10.1002/9780470015902.a0003211.pub2 [PDF Copy]
- Buffum, W., S. McWilliams, P.V. August. 2011. A spatial analysis of forest management and its contribution to maintaining the extent of shrubland habitat in southern New England, United States. JOURNAL OF FOREST ECOLOGY AND MANAGEMENT 262:1775-1785. [PDF Copy]
- Aamidor, S., U. Bauchinger, O. Mizrahy, S.R. McWilliams, B. Pinshow. 2011. Blackcap (Sylvia atricapilla) re-fuelling when dietary protein may be limiting: seasonal differences and behavioral compensation. INTEGRATIVE AND COMPARATIVE BIOLOGY, in press. [PDF Copy]
- McCue, M.D., A. Smith, R. McKinney, B. Rewald, B. Pinshow, S.R. McWilliams. 2012. A mass balance approach to identify and compare differential routing of 13C-labeled carbohydrates, lipids, and proteins in vivo. PHYSIOLOGICAL AND BIOCHEMICAL ZOOLOGY 84: in press. [PDF Copy]
- Blomberg, E., B.C Tefft, J.M. Reed, S.R. McWilliams. 2011. Evaluating spatially explicit viability of a declining ruffed grouse population. JOURNAL OF WILDLIFE MANAGEMENT, in press. [PDF Copy]
- McWilliams, S.R., E. Adkins-Regan, C. Vleck. 2012. How birds work: avian physiology within an ecological context. Chapter 7 in Cornell Ornithology Laboratory, Handbook of Bird Biology. Cornell University Press, Ithaca. [PDF Copy Not Available]
- Price, E.R., U. Bauchinger, D.M. Zajac, D.J. Cerasale, J.T. McFarlan, A.R. Gerson, S.R. McWilliams, C.G. Guglielmo. 2011. Migration- and exercise-induced changes to flight muscle size in migratory birds and association with IGF1 and myostatin mRNA expression. JOURNAL OF EXPERIMENTAL BIOLOGY, in press.[PDF Copy]
- Mizrahy, O., U. Bauchinger, S. Aamidor, S. McWilliams, B. Pinshow. 2011. Availability of water affects renewal of tissues in migratory blackcaps during stopover. Integrative and Comparative Biology, in press. [PDF Copy]
- Ben-Hamo, M., M. McCue, S. McWilliams, B. Pinshow. 2011. Dietary fatty acid composition influences tissue lipid profiles and regulation of body temperature in Japanese quail. JOURNAL OF COMPARATIVE PHYSIOLOGY B, in press. [PDF Copy]
- McCue, M.D., S.R. McWilliams, B. Pinshow. 2011. Ontogeny and nutritional status influence oxidative kinetics of nutrients and whole-animal bioenergetics in Zebra Finches, Taeniopygia guttata: new applications for 13C breath testing. PHYSIOLOGICAL AND BIOCHEMICAL ZOOLOGY 84, in press. [PDF Copy]
- Bauchinger, U., S.R. McWilliams, B. Pinshow. 2011. Reduced body mass gain during migratory stopover under simulated heat wave. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY 158A:374-381. [PDF Copy]
- Bauchinger, U, S.R. McWilliams, H. Kolb, V.M. Popenko, E.R. Price, H. Biebach. 2011. Flight muscle shape reliably predicts flight muscle mass of migratory songbirds: a new tool for field ornithologists. JOURNAL OF ORNITHOLOGY 152: 507-510. [PDF Copy]
- Langlois, L. and S.R. McWilliams. 2010. Protein requirements of an omnivorous and granivorous songbird decrease during migration. AUK 127:850-862. [PDF Copy]
- Bauchinger, U. and S.R. McWilliams. 2010. Extent of phenotypic flexibility during long-distance flight is determined by tissue-specific turnover rates: a new hypothesis. JOURNAL OF AVIAN BIOLOGY 41:1-7. [PDF Copy]
- Ladin, Z.S., P.M. Castelli, C.K. Williams, S.R. McWilliams. 2011. Time energy budgets and food use of Atlantic Brant across their wintering range. JOURNAL OF WILDLIFE MANAGEMENT, in press. [PDF Copy]
- Ben-Hamo, M., B. Pinshow, M. McCue, S. McWilliams, U. Bauchinger. 2010. Fasting triggers hypothermia, and ambient temperature modulates its depth in Japanese Quail Coturnix japonica. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY 156A:84-91. [PDF Copy]
- McWilliams, S.R. and M. Whitman. 2010. Non-destructive techniques to assess body composition of birds: TOBEC, D2O, FAT, DEXA, MRI, and other options. JOURNAL OF ORNITHOLOGY, in press. [PDF Copy Not Available]
- McCue, M. D., O. Sivan, S.R. McWilliams, and B. Pinshow. 2010. Tracking the oxidative kinetics of carbohydrates, amino acids, and fatty acids in the house sparrow using exhaled 13CO2. JOURNAL OF EXPERIMENTAL BIOLOGY 213:782-789. [PDF Copy]
- DesRochers, D.W., S.R. McWilliams, and J.M. Reed. 2010. Evaluating if energy and protein limit abundance of Hawaiian Moorhen. JOURNAL OF WILDLIFE MANAGEMENT 74:788-795. [PDF Copy]
- Smith, S.B. and S.R. McWilliams. 2010. Patterns of fuel use and storage in migrating passerines in relation to fruit resources at autumn stopover sites. AUK 127:108-118. [PDF Copy]
- Bauchinger, U., J. Keil, R. McKinney, J. M.Starck, and S.R. McWilliams. 2010. Exposure to cold but not exercise increases carbon turnover rates in specific tissues of a passerine. JOURNAL OF EXPERIMENTAL BIOLOGY 213:526-534. [PDF Copy]
- Blomberg, E., S.R. McWilliams, B. Tefft, E. Endrulat. 2009. Predicting landscape-scale habitat distribution for ruffed grouse using presence-only data. JOURNAL OF WILDLIFE BIOLOGY 15:380-394. [PDF Copy]
- Bauchinger, U. and S.R. McWilliams. 2009. Carbon turnover in tissues of a passerine bird: allometry, isotopic clocks, and phenotypic flexibility in organ size. PHYSIOLOGICAL AND BIOCHEMICAL ZOOLOGY 82:787-797. [PDF Copy]
- McCue, M. D., O. Amitai, I. Khozin-Goldberg, S. R. McWilliams, and B. Pinshow. 2009. Effect of dietary fatty acid composition on fatty acid profiles of polar and neutral lipid tissue fractions in zebra finches, Taeniopygia guttata”. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY 154A:165-172. [PDF Copy]
- DesRochers, D.W., S.R. McWilliams, M.D. Silbernagle, and J.M. Reed. 2009. Macronutrient profiles of wetland plants consumed by the Hawaiian Moorhen (Gallinula chloropus sandvicensis). WETLANDS 29: 845-853. [PDF Copy]
- Smith, S.A. and S.R. McWilliams. 2009. Dietary macronutrients affect lipid metabolites and body composition of a migratory passerine, the White-throated Sparrow (Zonotrichia albicollis). PHYSIOLOGICAL AND BIOCHEMICAL ZOOLOGY 82:258-269. [PDF Copy]
- Kurvers, R.H.J.M., M.L. Roberts, S.R. McWilliams, A. Peters. 2008. Experimental manipulation of testosterone and condition during molt affects activity and vocalizations of male blue tits. Hormones and Behavior 54:263-269.[PDF Copy]
- Smith, S.B., K.H. McPherson, J. Backer, B.J. Pierce, D. Podlesak, S.R. McWilliams. 2007. Fruit quality and consumption by songbirds during autumn migration. WILSON JOURNAL OF ORNITHOLOGY 119:419-428.[PDF Copy]
- Schneider, E. G., and S. R. McWilliams. 2007. Using nest temperature to estimate nest attendance of piping plovers. JOURNAL OF WILDLIFE MANAGEMENT 71:1998-2006. [PDF Copy]
- Podlesak, D. and S.R. McWilliams. 2007. Metabolic routing of dietary nutrients in birds: effects of dietary lipid composition on d13C of depot fat and its ecological implications. AUK 124:916-925. [PDF Copy]
- McWilliams, S.R., T. Sloat, C.A. Toft, and D. Hatch. 2007. Effects of prescribed fall burning on a wetland plant community with implications for management of plants and herbivores. WESTERN NORTH AMERICAN NATURALIST 67:299-317. [PDF Copy]
- McKinney, R.A., S.R. McWilliams, M.A. Charpentier. 2007. Habitat characteristics associated with the distribution and abundance of Histrionicus histrionicus (Harlequin Ducks) wintering in southern New England. NORTHEASTERN NATURALIST 14:159-170. [PDF Copy]
- Smith, S.B., S.R. McWilliams, and C. Guglielmo. 2007. Effect of diet composition on plasma metabolite profiles in a migratory songbird. CONDOR 109:48-58. [PDF Copy]
- McKinney, R.A., S.R. McWilliams, and M.A. Charpentier. 2006. Waterfowl-habitat associations during winter in an urban eastern North Atlantic estuary. BIOLOGICAL CONSERVATION 132:239-249. [PDF Copy]
- Muller, M., S.R. McWilliams, D. Podlesak, J. Donaldson, and R. Lindroth. 2006. Tri-trophic direct and indirect effects of plant defenses: Black-capped chickadees choose to eat gypsy moth caterpillars based on host leaf chemistry. OIKOS 114:507-517. [PDF Copy]
- Podlesak, D. and S.R. McWilliams. 2006. Metabolic routing of dietary nutrients in birds: effects of diet quality and macronutrient composition revealed using stable isotopes. PHYSIOLOGICAL AND BIOCHEMICAL ZOOLOGY 79:534-549. [PDF Copy]
- Endrulat, E.G., S.R. McWilliams, and B.C. Tefft. 2005. Habitat selection and home range size of ruffed grouse in Rhode Island. NORTHEASTERN NATURALIST 12:411-424. [PDF Copy]
- McKinney, R.A. and S.R. McWilliams. 2005. A new model to estimate daily energy expenditure for wintering waterfowl. Wilson Bulletin 117:44-55. [PDF Copy]
- Podlesak, D., S.R. McWilliams, K. Hatch. 2005. Stable isotopes in breath and blood indicate metabolism of dietary nutrients in small migratory songbirds. OECOLOGIA 142:501-510. [PDF Copy]
- Pierce, B.J. and McWilliams, S.R. 2005. Seasonal changes in composition of lipid stores in migratory birds: causes and consequences. CONDOR 107:269-279. [PDF Copy]
- Pierce, B.J., S.R. McWilliams, T. O’Connor, A.R. Place, C. Guglielmo. 2005. Effect of dietary fatty acid composition on depot fat and exercise performance in red-eyed vireos: implications for songbirds during migration. JOURNAL OF EXPERIMENTAL BIOLOGY 208:1277-1285. [PDF Copy]
- Servello, F.A., E. C. Hellgren, and S. R. McWilliams. 2005. Techniques for wildlife nutritional ecology. Pp. 554-590, In C.E. Braun, ed. Techniques for Wildlife Investigations and Management. Sixth Edition. The Wildlife Society, Bethesda, Maryland. [PDF Copy Not Available]
- Karasov, W.H. and S. R. McWilliams. 2005. Digestive constraint in mammalian and avian ecology. In: J.M. Starck and T. Wang (eds). Physiological and ecological consequences of feeding in vertebrates. Science Publishers Inc., India. [PDF Copy]
- McWilliams, S.R. and J.O. Leafloor. 2005. Effects of elevated CO2 on keystone herbivores in Arctic ecosystems. In: J. Ehleringer, T. Cerling, and D. Dearing (eds) A history of atmospheric CO2 and its effects on plants, animals, and ecosystems. Springer-Verlag. [PDF Copy]
- McWilliams, S.R. and W.H. Karasov. 2005. Migration takes guts: digestive physiology of migratory birds and its ecological significance. Pp. 67-78 In: P. Marra and R. Greenberg (eds) Birds of Two Worlds. Smithsonian Institution Press, Washington, D.C. [PDF Copy]
- McWilliams, S. R. and D. G. Raveling. 2004. Energetics and time allocation in Cackling Canada geese. BIOLOGY AND MANAGEMENT OF CANADA GEESE. Proceedings of the 2 International Canada Goose Symposium, Milwaukee, Wisonsin. [PDF Copy]
- McKinney, R.A., S.M. Glatt, and S.R. McWilliams. 2004. Allometric length-weight relationships for benthic prey of aquatic wildlife in coastal marine habitats. WILDLIFE BIOLOGY 10:241-249. [PDF Copy]
- McWilliams, S.R., B.J. Pierce, C. Guglielmo, M. Klaassen. 2004. Flying, fasting, and feeding in birds during migration: a physiological ecology perspective. JOURNAL OF AVIAN BIOLOGY 35:377-393. [PDF Copy]
- Pierce, B.J., S.R. McWilliams, A.R. Place, M.A. Huguenin. 2004. Diet preferences for specific fatty acids and their effect on composition of fat reserves in migratory Red-eyed Vireos (Vireo olivaceous). COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY 138:503-514. [PDF Copy]
- Pierce, B.J. and S.R. McWilliams. 2004. Diet quality and food limitation affect the dynamics of body composition and digestive organs in a migratory songbird (Zonotrichia albicollis). PHYSIOLOGICAL AND BIOCHEMICAL ZOOLOGY 77(3):471-483. [PDF Copy]
- Frazer, K.I. and S.R. McWilliams. 2002. Determinants of dietary preference in yellow-rumped warblers. WILSON BULLETIN 114:243-248. [PDF Copy]
- McWilliams, S. R., S. Kearney, and W. H. Karasov. 2002. Dietary preferences of warblers for specific fatty acids in relation to nutritional requirements and digestive capabilities. JOURNAL OF AVIAN BIOLOGY 33:167-174.[PDF Copy]
- McWilliams, S.R. and W.H. Karasov. 2001. Phenotypic flexibility in digestive system structure and function in migratory birds and its ecological implications. Comparative Biochemistry and Physiology 128A:579-593. [PDF Copy]
- McWilliams, S.R. 2000. Avoiding extreme environments: migratory birds. MARITIMES Summer ’00:22-24.[PDF Copy Not Available]
- McWilliams, S.R. 2002. Vertebrate nutritional ecology. Encyclopedia of Life Sciences, United Kingdom. [PDF Copy]
- 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. [PDF Copy]
- McWilliams, S.R., E. Caviedes-Vidal, and W.H. Karasov. 1999. Digestive adjustments in cedar waxwings to high feding rates. JOURNAL OF EXPERIMENTAL ZOOLOGY 283:394-407. [PDF Copy]
- McWilliams, S. R. and W. H. Karasov. 1998. Test of a digestion optimization model: effect of variable-reward feeding schedules on digestive performance of a migratory bird. OECOLOGIA 114:160-169. [PDF Copy]
- 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.[PDF Copy]
- 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. [PDF Copy]
- 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.[PDF Copy]
- Afik, D., S. R. McWilliams, and W. H. Karasov. 1997. Test for passive absorption of glucose in the yellow-rumped warbler and its ecological implications. PHYSIOLOGICAL ZOOLOGY 70:370-377. [PDF Copy]
- McWilliams, S. R., J. P. Dunn, D. G. Raveling. 1994. Predator-prey interactions between eagles and cackling Canada and Ross’ geese during winter in California. WILSON BULLETIN 106:272-288. [PDF Copy]
- McWilliams, S. R. 1992. Courtship behavior of the small-mouthed salamander (Ambystoma texanum): the effects of conspecific males on male mating tactics. BEHAVIOUR 121:1-19. [PDF Copy]
- McWilliams, S. R. and M. D. Bachmann. 1989. Predatory behavior of larval small-mouthed salamanders,Ambystoma texanum. HERPETOLOGICA 45:459-464. [PDF Copy]
- McWilliams, S. R. and M. D. Bachmann. 1989. Foraging ecology and prey preference of pond-form larval small-mouthed salamanders, Ambystoma texanum. COPEIA 1989: 948-961. [PDF Copy]
- McWilliams, S.R. and M. D. Bachmann. 1988. Using life history and ecology as tools to manage a threatened salmander species. JOURNAL OF IOWA ACADEMY OF SCIENCES 95: 66-71. [PDF Copy]