Influences of Weather Conditions, Natural Food Abundance, and the Spacing of Feeders on the Feeding-Table Use by Japanese Squirrels Sciurus lis in a Suburban Forest

Abstract

The purpose of this study was to examine the influences of seasonal and annual changes in weather conditions, natural food abundance (pine seeds), and the spacing of feeders on the use of walnuts on feeding tables by Japanese squirrels (Sciurus lis) in a suburban forest in Nagoya City, in summer (Jul–Aug) and autumn (Sep–Oct) from 2019 to 2021. Feeder-use increased in severe weather conditions, i.e., low temperature and heavy rain in both seasons, and decreased in summer of the year when pine-seeds were abundant. Feeders were used more in autumn for hoarding before the winter. The intervals among eight feeding tables were widened during the study from c. 100 m in 2019–2020 to c. 300 m in 2021. In the years when the feeders were placed at short intervals, we found two behavioral modifications due to the supplemental feeding: a concentrated distribution of many individuals in 2019 and exclusive occupation by a particular female in 2020. In contrast, in 2021 with the feeding tables placed at wider intervals, the distribution of individuals expanded over the entire study area, and the use of supplementary feeding decreased, while seed consumption increased.