Acorn Preference and Habitat Use in Eastern Chipmunks

-We used field and laboratory trials to examine the effects of size and species of acorn on food choice by eastern chipmunks (Tamius striatus) from central New York. Initial trials suggested that chipmunks preferred the low tannin, white oak (W; Quercus alba) acorns over the high tannin, red oak acorn (R; Q. rubra). However, the smaller size of the W acorns, and therefore greater ease of handling, possibly confounded the affects of tannin content on acorn choice. Additional field and laboratory experiments confirmed that chipmunks preferred smaller acorns, but W acorns were still preferred to equal-sized R acorns. Frequency of live capture of chipmunks during the period of acorn drop (midSeptember to mid-November) at the field site was related directly to the total basal area (P -0.02) but not number of W trees. Capture frequency was also correlated negatively with the number (P = 0.04) but not basal area of R trees in the canopy. Our results suggest that chipmunks prefer to eat W acorns and that chipmunk activity is in part influenced by this preference. Heavy chipmunk harvesting of the preferred W acorns may be influencing the successional patterns in the forest at our study site.