Individual characteristics, experience, and environmental conditions shape large‐scale patterns of animal activity timing

The timing of an animal's activity affects its survival and reproduction because timing determines the nature of every interaction an organism has with its environment. Although the timing of activity may depend on aspects of the individual (e.g., body mass, reproductive status, experience) or the nature of the environment (e.g., temperature, precipitation, abundance of congeners), we lack studies that evaluate timing of large numbers of conspecifics spanning an array of environmental conditions. We quantified the timing of activity onset (measured as the time when an individual was captured) for 1749 capture events of 716 individual white‐footed mice ( Peromyscus leucopus ) sampled in 2022 and 2023 at eight sites in the National Ecological Observatory Network (NEON) across the upper midwestern and eastern United States. We found strong effects of body mass, sex, and prior capture experience on activity onset. Larger individuals, reproductive females, and individuals with previous capture experience were all captured earlier in the night. Extrinsic factors also influenced activity onset: Animals were captured earlier when temperatures were warmer, later on nights with precipitation, and earlier as the density of congeners increased. Individual traits interacted with extrinsic factors to influence activity onset, as the shift to earlier capture with increasing capture experience was greatest for smaller individuals, and only reproductive females were active earlier (not males or nonreproductive females). Overall, our results indicated a strong role for individual and environmental factors on the timing of activity onset: Individuals modified the timing of activity onset in response to environmental conditions, used experience to potentially increase resource acquisition (earlier activity following initial capture), and shifted activity in more‐competitive environments (earlier activity when density of conspecifics was high). Our results provide broad evidence of learning by wild rodents across a large extent of the species' geographic range, suggesting that use of experience to modify behavior is common for animals in natural environments. Moreover, our results indicate that traits that vary among individuals (e.g., sex, age) and within individuals (experience) are essential for predicting changes in individual behavior as well as potential changes in interactions mediated by individual activity (e.g., competition, predation, and disease dynamics).