Increased overwinter mortalities of white-tailed deer (Odocoileus virginianus) fawns during a drought year

Marie I. Tosa, Matthew T. Springer, Eric M. Schauber, Clayton K. Nielsen

Research output: Contribution to journalArticlepeer-review


Mortality rates of white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) fawns have been quantified throughout North America. Few studies, however, have assessed cause-specific mortality of fawns after the first 3 months of life or during a severe weather event. During 2010–2014, we captured and radio-tracked 93 fawns in southern and central Illinois and recorded 18 mortality events. In order of importance, survival rates were affected by days since capture, year of drought, age at capture, week after capture (1 or 0 indicator), and region. Estimated overwinter (fall through spring) survival rate (±SE) of fawns in both regions during 2010–2014 was 0.83 ± 0.04. However, estimated overwinter survival rates were depressed during 2012–2013, following the severe drought of 2012 (0.63 ± 0.11 or 0.66 ± 0.11 depending on the model). Main causes of mortality were capture-related and predation, though some dead deer also showed signs of hemorrhagic disease. We suspect that the extreme drought of 2012 created favorable conditions for fall–spring mortality of fawns, due to elevated disease transmission and lower forage quality and quantity for deer. In addition, drought may have contributed to predation by reducing abundance of alternative prey. Our results suggest that severe weather conditions during summer can substantially impact overwinter fawn survival.

Original languageEnglish (US)
Pages (from-to)55-61
Number of pages7
JournalCanadian journal of zoology
Issue number1
StatePublished - 2018
Externally publishedYes


  • Bobcat
  • Drought
  • Illinois
  • Lynx rufus
  • Mortality
  • Odocoileus virginianus
  • Predation
  • Survival
  • White-tailed deer

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology


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