Mississippi State University

Raccoon (Procyon lotor)

Influence of Weather on Movement and Activity


Results

Using multiple linear regression to model movement rates as a function of seasonal weather conditions, during breeding-gestation movement rates were most related to temperature, wind direction, wind speed, and barometric pressure. Raccoon movement rates generally increased with decreasing barometric pressure and increasing temperature. During fall-winter, movement rates were most related to relative humidity and temperature. Movement rates generally increased with decreasing humidity and increasing temperature. During parturition-young rearing, movement rates were most related to barometric pressure and relative humidity.

Using logistic regression to model seasonal activity as a function of weather conditions, during breeding-gestation wind direction, dewpoint, barometric pressure, and temperature were most related to changes in activity. Activity generally decreased with corresponding decreases in temperature, barometric pressure, and dewpoint. During fall-winter, relative humidity and temperature were most related to changes in activity. Activity generally increased with increasing temperature, but decreased as humidity rose. During parturition-young rearing, temperature, relative humidity, and barometric pressure were most related to changes in activity. Activity generally increased with increasing temperature and barometric pressure, but decreased with increasing humidity.

Summary

Our results suggest that weather conditions do affect raccoon movement rates. However, our models accounted for little variation in movement rates, suggesting that weather conditions contributed little to temporal variability in movement rates. The fact that variables were selected as being significant, yet accounted for minimal variation in movement rates is likely a function of large sample sizes. Raccoon movements did appear to consistently be influenced by temperature and relative humidity as these variables were selected within several models. Previous researchers have suggested that temperature and humidity influence raccoon movements in other landscapes. However, we stress caution when interpreting these results, particularly when extrapolated beyond our study area. Based on our results, it appears that perhaps a single weather station, regardless of accuracy and precision, cannot monitor weather conditions at the resolution needed to examine relationships between weather conditions and movement. We suggest researchers consider monitoring weather conditions at a finer scale with similar or improved equipment in different landscapes.

Results from our study suggest that weather conditions influence raccoon activity patterns seasonally. Our models provided variable classification rates; however, several models correctly classified >70% of active and inactive locations. Previous studies have reported that low temperatures tended to decrease raccoon activity and that raccoons were more active on warm nights during winter. Our data support these findings as temperature was related to raccoon activity in fall-winter during diurnal and nocturnal periods. In fact, raccoon activity decreased with declining temperatures in nocturnal periods. Similarly, activity was positively related to increasing diurnal temperatures. Although speculation exists that raccoons may become more active on nights following rain events, raccoons on TWMA and GP tended to increase activity with decreasing barometric pressure, which occurs as fronts approach. Hence, our data suggest that raccoons may be more active prior to weather fronts, rather than immediately after.