Caldwell Hahn, Ph.D.


Dr. Caldwell Hahn  works on wildlife disease and ecological immunology.   She is currently collaborating to use peptide arrays to characterize the immune and metabolic responses of black and mallard ducks (Anas spp). to avian influenza.  She is also characterizing the innate immune responses (degranulation & oxidative burst) of several duck species at the PWRC waterfowl complex, including black duck and lesser scaup, a diving duck.  Previously Dr. Hahn characterized the immune responses of both raptors and songbirds utilizing experimental infection with the invasive West Nile virus (WNV) and endemic encephalitis viruses (SLEV, WEEV).    She has also worked with CDC, Dr. Nicholas Komar, and University of Colorado Vet School, Drs Richard Bowen and Nicole Nemeth, passive immunity of screech owls to WNV via maternal antibodies.  Dr. Hahn began to work on how immune adaptations are shaped by species’ niche and life history while working with the New World cowbirds, a genus of avian brood parasites (Molothrus, Icteridae).  Her initial discovery that the principal North American brood parasite, the brown-headed cowbird, inhabits a niche with heightened exposure to ectoparasites (avian lice ; Phthiraptera) led to her examining and characterizing several of the  cowbird’s immune adaptations to its parasitic life history strategy,  including: (1) greater resistance to infection with WNV and other virulent encephalitis viruses when compared with related, non-parasitic species;  (2) more effective innate immune responses (degranulation and oxidative burst);  and (3) higher levels of particular immune components in their eggs.  She is also investigating relationships between immune and endocrine adaptations.

Recent Accomplishments


  • Harvard University, Museum of Comparative Zoology, Post-doctoral Fellow in Sociobiology, advisor Bert Holldober
  • Smithsonian Tropical Research Center, Post-doctoral Fellow in Sociobiology,  advisor Mary Jane West Eberhard
  • Rutgers University, Ph.D., Institute of Animal Behavior, behavioral ecology, advisor Colin Beer,  Richard D. Alexander
  • Tufts University, M.S.,  animal behavior, advisor, Benjamin Dane
  • Wellesley College, B.A.

Professional Studies/Experience

  • Geological Survey, Patuxent Wildlife Research Center, Research Biologist, 1990-present
  • Rutgers University, Adjunct Faculty, 2007-present
  • Smithsonian Institution, Research Associate 1995-1998
  • US Fish & Wildlife Service –Fort Collins Science Center, 1988-1990
  • National Academy Sciences, IOM, 1986-1988
  • Agency for International Development, 1982-1985
  • World Wildlife Fund, 1980-1982


  • Rutgers University, Adjunct Faculty, 2007-present

Professional societies/affiliations/committees/editorial boards

Honors, awards, recognition, elected offices

Scientific/Oral Presentations, Abstracts

  • University of Pennsylvania, winter 2016, “How has the niche of a brood parasite shaped its immune responses?”
  • Invited speaker, Huck Institute of Life Sciences, Penn State University, spring, 2012. "Invasive Species & Climate Change:  the role of immunity"
  • Invited speaker, Ethological Society Meeting on Cooperation and Conflict, Zurich, 2011
  • Invited speaker, European Society Evolutionary Biology, Turino, 2009.  "Enhanced Innate Immunity Favored in a Parasite-rich environment"
  • Invited seminar, Institute for Ecology, University of Bern, Switzerland, 2009
  • Fellow, American Ornithological Union
  • Invited seminar, Children’s Hospital, Ludwig-Maximilians University, Munich, 2009.  "The Hygiene Hypothsis Examined in a Model Wildlife Species"
  • Invited speaker, Jacques Monod Conference “Genetics of Host-Parasite Coevolution”, French National Science Foundation, Roscoff, France, September 2007.
  • Invited speaker, Dept. Ecology & Evolution, University of Lausanne, Switzerland, 2007
  • Invited presentation, Symposium on Evolutionary Biology & Human Health, American Institute of Biological Sciences (AIBS), Washington, DC, 2007
  •  Invited speaker, University of Fribourg, Workshop on Evolution, Switzerland, February, 2002.
  • Invited Speaker, Conference on Innovation in the Biosciences, Marie Curie Fellowship Association, Bedford, England, 2000.
  • Invited Speaker, European Science Foundation, Workshop on Host-Parasite Coevolution, Perpignan, France, 1999
  • 1997 Invited speaker, Partners in Flight Symposium on Cowbird Management, Sacramento,