Alfred M. Dufty,
Jr.
Professor, Department of Biology and Associate Dean
of the Graduate College
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Behavioral endocrinology - One general focus of my research
is the relationship between hormones and behavior. I study this relationship
both in the field and in the laboratory. Free-living animals are observed
closely to determine their mating status, breeding stage, and/or social rank.
These animals are captured and a blood sample is taken quickly. My
radioimmunoassay laboratory can measure plasma steroid hormones levels, such as
testosterone, estradiol and corticosterone. Additional nutritional and metabolic
parameters from the blood can be assessed with an autoanalyzer. Further
manipulation and testing can be done on captive animals. Using these tools I can
obtain an indication of an animal's body condition, its level of stress, and
hormonal correlates of aggressive, territorial or reproductive behavior, etc.
Aspects of my work are applicable to conservation biology, through exploration
of the ecological and physiological responses of animals to environmental
perturbation.
Feathers, breeding sites, and stable isotopes - Two of my
current graduate students are using stable isotope analysis of feathers to link
raptors (Northern goshawks and red-tailed hawks) to their breeding grounds. The
process works like this: Elements occur in multiple forms, or isotopes, which
differ in the number of neutron they contain. For example, the most common form
of hydrogen, 1H, has a single neutron, whereas the deuterium isotope, 2H,
has two. The ratio of these isotopes in the environment varies with latitude. When animals feed, stable isotopes of an element are incorporated into their
tissues in the same ratio as in the environment. For most tissues this is a
dynamic process, and the isotope signature of a tissue changes as the animal
moves to new areas and ingests nutrients containing different isotopic ratios.
But feathers become inert after they develop. Thus, the isotopic signature of
the environment in which the feather developed is locked into the feather and
remains constant, even if the bird migrates to a different latitude. The stable
isotope ratios of feathers collected during migration or on wintering grounds
can be determined by mass spectrometry, and the general latitudinal range in
which the bird grew the feather, which is usually the breeding grounds, can be
estimated.
Natal dispersal - I am interested in the relationship among hormones, body condition, and natal dispersal in animals. Dr. James Belthoff and I conducted an NSF-sponsored study of these factors in fledgling western screech-owls. By combining field and laboratory studies, using observational and manipulative techniques, we investigated the factors that determine when a bird leaves its natal territory. I also have been looking at the effect of stress during pregnancy on dispersal behavior of offspring in the common lizard in France.
Brood parasitism - A long-term focus of my research is the behavior and ecology of the brood parasitic brown-headed cowbird. Cowbirds lay their eggs in other birds' nests, and these foster-parents frequently raise the young cowbirds as if they were their own. This unusual breeding strategy, with its absence of parental care, has physiological and behavioral implications for cowbirds. I have explored the hormonal correlates of breeding activity in thisspecies, as well as the use of vocalizations in cowbird social interactions. I also am examining the relationship between cowbirds and an infrequently-used host, the yellow-headed blackbird.
Dufty, A. M., Jr. In press. Stress responsiveness in nestlings: A comparison of two sampling techniques. Auk.
Vercken, E., M. de Fraipont, A. M. Dufty, Jr., and J. Clobert. In press. Mothers timing and duration of corticosterone exposure modulate offspring size and natal dispersal in the common lizard (Lacerta vivipara). General and Comparative Endocrinology.
Leppert, L., T. V. Zadorozhny, J. R. Belthoff, A. M. Dufty, Jr., S. L. Stock, G. Kaltenecker, and J. F. Smith. 2006. DNA sexing of owls: a comparison of three methods. Journal of Raptor Research 40:291-294.
Donohue, K. C. and A. M. Dufty, Jr. 2006. Sex
determination in Red-tailed Hawks (Buteo jamaicensis calurus) using DNA
analysis and morphometrics. Journal of Field Ornithology 77:74-79.
Dufty, A. M., Jr. and M. B. Crandall. 2005. Corticosterone secretion in response to adult alarm calls in American Kestrels. Journal of Field Ornithology 76:319-325.
Smith, A. D. and A. M. Dufty, Jr. 2005. Variation in the stable-hydrogen isotope composition of Northern goshawk feathers: relevance to the study of migratory origins. Condor 107:547-558.
Dufty, A. M., Jr. and Danchin, E. 2005. Development of the phenotype. Pp. 89-127. In: Behavioral Ecology: An Evolutionary Perspective on Behavior. (E. Danchin, et al., eds.). Dunod, Paris.
Holberton, R. L. and A. M. Dufty, Jr. 2005. Hormones and variation in life history strategies of migratory and non-migratory birds. Pp. 290-302. In: Birds of Two Worlds (R. Greenberg and P. P. Marra, eds.). Johns Hopkins University Press, Baltimore, MD.
Hanauska-Brown, L. A., A. M. Dufty, Jr., and G. J. Roloff. 2003. Blood chemistry, cytology, and body condition in adult northern goshawks (Accipiter gentilis). Journal of Raptor Research 37:299-306.
Meylan, S., A. M. Dufty, Jr, and J. Clobert. 2003. The effect of transdermal corticosterone application on plasma corticosterone levels in pregnant Lacerta vivipara. Comparative Biochemistry and Physiology 134:497-503.
Dufty, A. M., Jr., J. Clobert, and A. P. Moller. 2002. Hormones, developmental plasticity and adaptation. Trends in Ecology and Evolution 17:190-196.
Dufty, A. M., Jr. and J. R. Belthoff. 2001. Proximate mechanisms of dispersal: the role of hormones and body condition. In: Dispersal (J. Clobert et al., eds.), pp. 217-229. Oxford Univ. Press, London.
Dufty, A. M., Jr. 2000. Cowbird brood parasitism on a little-used host: the yellow-headed blackbird. In: The Ecology and Management of Cowbirds (J.M.N. Smith, et al., eds.), pp. 115-119. Univ. of Texas Press, Austin.
Dufty, A. M., Jr. and A. Hanson. 1999. Vocal and behavioral responses of brown-headed cowbirds to flight whistles from different dialects. Condor 101:484-492.
Heath, J. A. and A. M. Dufty, Jr. 1998. Body condition and the adrenal stress response in captive American kestrel juveniles. Physiological Zoology 71:67-73.
Belthoff, J. R. and A. M. Dufty, Jr. 1997. Corticosterone, body condition, and locomotor activity: a model for natal dispersal in birds. Animal Behaviour 71:67-73.
Dufty, A. M., Jr. and J. R. Belthoff.1997. Corticosterone and the stress response in juvenile western screech-owls: effects of captivity, gender, and activity period. Physiological Zoology 70:143-149.
Belthoff, J. R. and A. M. Dufty, Jr. 1995. Locomotor activity levels and the dispersal of western screech-owls, Otus kennicottii. Animal Behaviour 50: 558-561.
Butler, Mike (2006) Currently in a doctoral program in
the School of Life Sciences at Arizona State University.
Thesis title: Neonatal Stress and Avian Development: Effects on Growth,
Immune Function, and Plumage
Holman, Shanie (2001) Currently in the Biology
Department at Lake Washington Technical College, Kirkland, WA.
Thesis title: The Adrenocortical Response to Handling Stress in Two
Temperate-Breeding Blackbird Species
Leppert, Lynda (2002) Currently the Laboratory
Coordinator in the Department of Biology, University of Memphis.
Thesis title: Heterophil to lymphocyte ratios and DNA sexing in fall
migrating northern saw-whet owls and flammulated owls in Idaho
Smith, Adam (2006) Currently with the Avian Research &
Monitoring, Wildlife Diversity Program in the Kentucky Department of Fish and
Wildlife Resources.
Thesis title: Exploring Raptor Migration using Stable Isotope Analysis: the
Northern Goshawk in Western North America
Staley, Airica (2003) Currently a Research Technician in
the Department of Biomedical Sciences at Colorado State University.
Thesis title: Noninvasive Fecal Steroid Measures for Assessing Gonadal and
Adrenal Function in the Golden Eagle (Aquila Chrysaetos) and Peregrine Falcon (Falco
Peregrinus)
Whitman, Buddy (2006) Currently in a doctoral program in
the Department of Biology at the University of North Carolina .
Thesis title: The Effects of Neonatal Handling on Adrenocortical
Responsiveness, Morphological Development, and Corticosterone Binding Globulin
in American Kestrels (Falco sparverius) and European Starling (Sturnus vulgaris)
Berg, Melanie Thesis topic: Egg hormones in American
kestrels
Donohue, Kara Thesis topic: Stable isotopes in migrating Red-tailed hawk
feathers
Hallingstad, Eric Thesis topic: Seasonal variation in adrenoresponsiveness in
American kestrels
Marzot, Vittoria Thesis topic: Developmental stress and sexual selection in
American kestrels
Potential
Graduate andI seek self-motivated students who are interested in investigating the physiology and/or behavior of vertebrates, and who would like to learn field and laboratory techniques. I enjoy working with students and will spend the time that is necessary to train them to conduct their research projects. I do not micro-manage my students, and I expect them to be mature and responsible about completing their studies. I allow them latitude in developing their projects, and my door is always open to discuss questions and to solve problems.