Effects of artificial light on foraging behavior of the Pacific Kangaroo Rat (Dipodomys agilis)

Artificial light at night is increasingly recognized as a cause of habitat degradation, and as a conservation threat to wildlife species. We studied the behavioral response of Pacific kangaroo rats (Dipodomys agilis) to natural and artificial light in coastal sage scrub in southern California, United States. We used digital trail cameras to monitor visits to seed trays in shrub and open, intershrub microhabitats. Under natural-light conditions, kangaroo rats were more active on full- than new-moon nights, and concentrated foraging beneath shrubs. Surprisingly, kangaroo rats frequently interacted with other rodents in seed trays. Near to an artificial light source, kangaroo rats removed fewer seeds, had fewer foraging bouts, and spent less time in trays—especially in brightly lit open microhabitats—compared to distances farther from the light. Differences between the first and second nights of trials during both experiments suggested that kangaroo rats learned locations of resource-rich seed trays and modified their behavior accordingly. Our results are similar to recent studies showing that artificial light depresses foraging activity of rodents in the areas of highest illumination, and adds to evidence of the need to mitigate impacts of urban lighting in fragments of coastal sage scrub, especially along the urban–wildland interface.