Bias in the determination of temporal activity patterns of syntopic Peromyscus in the Southern Appalachians

Abstract

We compared inferred activity patterns of two syntopic rodents, Peromyscus leucopus and P. maniculatus, in western North Carolina. Activity patterns were derived from capture-frequency data obtained from Sherman live-traps equipped with digital timers following different trapping protocols. we tested the hypothesis that no differences would be observed in frequency distribution of captures from trapping grids monitored only in the morning (control) compared with grids where captured animals were released during the night and in the morning (treatment). Distributions of frequencies of captures on control and treatment grids were significantly different. On control grids, capture frequencies (based on 3-h intervals) of both species were higher in the first 3 h after sunset and decreased thereafter throughout the night, but frequencies of captures of both species were uniform throughout the night on treatment grids. Photographic records from automated cameras suggested increasing levels of activity throughout the night. Activity patterns derived from camera data were different from those derived from the control and treatment grids. Inferences regarding activity patterns are sensitive to method and trapping-protocol bias.