title: The effect of terrain and female density on survival of neonatal white-tailed deer and mule deer fawns.
abstract: Juvenile survival is a highly variable life-history trait that is critical to population growth. Antipredator tactics, including an animal's use of its physical and social environment, are critical to juvenile survival. Here, we tested the hypothesis that habitat and social characteristics influence coyote (Canis latrans) predation on white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) fawns in similar ways during the neonatal period. This would contrast to winter when the habitat and social characteristics that provide the most safety for each species differ. We monitored seven cohorts of white-tailed deer and mule deer fawns at a grassland study site in Alberta, Canada. We used logistic regression and a model selection procedure to determine how habitat characteristics, climatic conditions, and female density influenced fawn survival during the first 8 weeks of life. Fawn survival improved after springs with productive vegetation (high integrated Normalized Difference Vegetation Index values). Fawns that used steeper terrain were more likely to survive. Fawns of both species had improved survival in years with higher densities of mule deer females, but not with higher densities of white-tailed deer females, as predicted if they benefit from protection by mule deer. Our results suggest that topographical variation is a critical resource for neonates of many ungulate species, even species like white-tailed deer that use more gentle terrain when older. Further, our results raise the possibility that neonatal white-tailed fawns may benefit from associating with mule deer females, which may contribute to the expansion of white-tailed deer into areas occupied by mule deer.
authors.affiliation: Department of Biology University of Winnipeg Winnipeg R3B 2E9 Manitoba Canada; Present address: Department of Biology Memorial University of Newfoundland St. John's Newfoundland A1B 3X9 Canada.
authors.forename: Maegwin
authors.initials: M
authors.lastname: Bonar
authors.affiliation: Natural Resources Institute University of Manitoba Winnipeg R3T 2N2 Manitoba Canada.
authors.forename: Micheline
authors.initials: M
authors.lastname: Manseau
authors.affiliation: Natural Resources Institute University of Manitoba Winnipeg R3T 2N2 Manitoba Canada.
authors.forename: Justin
authors.initials: J
authors.lastname: Geisheimer
authors.affiliation: Department of Biology University of Winnipeg Winnipeg R3B 2E9 Manitoba Canada.
authors.forename: Travis
authors.initials: T
authors.lastname: Bannatyne
authors.affiliation: Department of Biology University of Winnipeg Winnipeg R3B 2E9 Manitoba Canada.
authors.forename: Susan
authors.initials: S
authors.lastname: Lingle
keywords: Antipredator behavior; NDVI; coyote predation; habitat use; species interactions