The Effects of Weather, Sex and Season on the Nocturnal Activity of Peromyscus truei (Rodentia)

The nocturnal activity of Peromyscus truei was investigated on a seasonal basis for one year. Females showed bimodal activity patterns during all seasons. Males were unimodal in the winter and differed significantly from the females during the spring. Activity was positively related to ambient temperature and negatively related to moonlight during the fall and winter months. Summer activity was positively related to cloud cover. Weather variables were good predictors of P. truei activity during the fall but less so during other seasons. The purpose of this paper is to elucidate some of the abiotic factors which are related to the nocturnal activity of Peromyscus truei, and to explore the effects of sex and season on the activity patterns of this species. Numerous studies have been concerned with the effects of weather on rodent activity (Gentry and Odum, 1957; Orr, 1959; Marten, 1973; O'Farrell, 1974; Blaustein and Fugle, 1981; Vickery and Bider, 1981) although few have investigated the role of sex or season. Most studies pool the data for both sexes and different seasons to achieve overall activity relationships. This paper reports on some of the environmental variables related to the nocturnal activity of P. truei and shows that the relationship between weather and activity is dependent on the season. Also, it will be shown that during some seasons male and female activity patterns differ considerably.