Date of Award
Master of Science
Natural Resource Ecology and Management
Julie A. Blanchong
Stephen J. Dinsmore
White-tailed deer (Odocoileus virginianus) are one of the most managed species in North America. Overabundant deer populations negatively affect vegetation communities, cause crop damage, and increase the risk of deer-vehicle collisions. To identify areas of management need and set accurate harvest quotas, managers need reliable estimates of deer population trends. Fawns suffer the highest rate of mortality of any age class, and it varies across their range in response to differences in landscape composition, predator community, and deer density. We radio-collared 48 fawns from 2015-2017 to document cause-specific mortality, estimate survival, and describe space use in central Iowa. Disease was the primary cause of mortality, followed by suspected predation and harvest. The estimated fawn survival rate was 0.78 through 30 days post-capture, 0.69 through 60 days post-capture, and 0.31 through 7 months post-capture. Declines in fawn survival through 7 months post-capture were the result of disease and harvest. Fawn home ranges were primarily comprised of woodland (>60%) and female fawns avoided agriculture. The proportion of nearby woodland had a positive effect on fawn survival. We used radio telemetry to estimate fawn locations and assess habitat selection. Locations derived from radio telemetry have inherent error that can bias habitat selection studies. We conducted trials to evaluate the effects of slope, observer experience, and fawn behavior on location accuracy. Location error varied among sites along a slope (P < 0.001); however, distance between sites and observer, not slope position, was the best explanation for differences in error. Location error did not differ between experienced and inexperienced observers (P > 0.05). Location error did not increase over time for radio-collared fawns (β = 0.005, 95% CI was -0.001, 0.010). Confidence ellipse area was an indicator of location error (β =0.87, 95% CI was 0.57, 1.18), which suggests it is an adequate proxy for accuracy of location estimates. Our finding of higher fawn survival in woodland habitat suggests that managers should maintain woodland habitat in agricultural regions. Disease caused most of our fawn mortality in contrast to predation as reported in other Midwestern studies. Our survival estimates through 30 and 60 days post-capture were similar to estimates from other Midwestern regions; however, survival through 7 months was much lower.
Mcgovern, Patrick, "Survival, space use, and radio telemetry accuracy of white-tailed deer fawns in central Iowa" (2018). Graduate Theses and Dissertations. 16635.