Factors affecting wildlife road-kills: The armadillo model

The common long-nosed (nine-banded) armadillo (Dasypus novemcinctus) is the only member of the family Dasypodidae (Edentata) found in the United States. Since it is one of the most common mammals found dead along Florida highways, the armadillo may serve as a model to study which factors affect wildlife road-kills. Armadillo diurnal activity and road-kills were examined along a 169-km stretch of the Florida Turnpike. We conducted 49 surveys during a 13-month period (1996-1997) that yielded 143 road-kill incidents and 173 observations of active armadillos. Activity and road-kills were spatially and temporally correlated with several factors (weather, soil quality, vegetation coverage, and traffic volume). During winter, armadillos are more diurnal and generally reduce their activity; thus, are less likely to be killed by vehicles. Activity in these months was concentrated near habitats with dense woodlands. In summer, armadillos are predominantly nocturnal and apparently more active. Consequently, their road-kill rates nearly doubled and were significantly correlated with night-time traffic volume, but not with vegetation. In conclusion, armadillos are most likely to be killed during summer nights. The relatively rarer winter kills tend to occur near habitats with high vegetation coverage, habitats with extensive diurnal activity along the right-of-way.