White-tailed deer roadside behavior, wildlife warning reflectors, and highway mortality

Abstract

The behavior of white-tailed deer ( Odocoileus virginianus) and the effect of Swareflex Wildlife Highway Warning Reflectors were studied along a busy two-lane highway in Crab Orchard National Wildlife Refuge, Illinois, U.S.A. Focal-animal observational sampling was conducted through all seasons and for 24 h day −1. Deer roadside activity was primarily between 17:00 and 07:00 h and appeared unaffected by weather conditions or traffic volume. During the baseline studies of Area I (bordered on one side by a corn field and on the other by hardwood forest), 70% of the observed deer crossed or attempted to cross the highway; feeding on the grassy right-of-way was observed in 32% of the sightings, mostly after corn was depleted. In Area II (bordered on both sides by hardwood forest), 36% of the observed deer crossed or attempted to cross the highway; 68% fed on the grassy right-of-way. In the presence of traffic, deer commonly looked up from feeding and stared at the approaching vehicle. Crossing behavior was similar in both areas; deer generally walked to the highway and stopped at the edge of the pavement before moving across. Adult females usually crossed in a relaxed, cautious manner. Fawns appeared less cautious and followed adult females. Adult and yearling males (rarely observed along the roadway) crossed with more excitement than adult females and fawns. After baseline data had been obtained, Swareflex reflectors were installed for 14 months in Area I while observational sampling continued. Deer roadkills occurring between dusk and dawn were the same with reflectors deployed as during the 2 years prior to testing, even though the deer population had decreased. Behavior of deer crossing the road did not appear to be altered by the reflectors.