CUES TO OPTIMAL FORAGING BY A CENTRAL-PLACE FORAGER: THE EASTERN CHIPMUNK, TAMIAS STRIATUS.

CUES TO OPTIMAL FORAGING BY A CENTRAL-PLACE FORAGER: THE EASTERN CHIPMUNK, TAMIAS STRIATUS. James E. Morris and Robert S. Lishak, Dept. of Biological Sciences, Auburn University, AL 36849

There has been much research done showing that foraging animals optimize their behavior to maximize their energetic returns. However, little research has sought to describe which specific cues a forager uses to alter its behavior for energetic optimization. Three specific variables were examined over the study period: microhabitat, food patch quality, and distance. Foraging was measured as giving-up density (GUD) using a wooden tray filled with a variable sand and seed mixture. Preliminary results involving nine individual chipmunks indicated a statistically significant multiple regression analysis, supporting past findings that an energetic optimization of foraging is occurring. The specific foraging cues were further analyzed individually. Microhabitat's relationship to GUD was in the expected direction, which is best described as a cue of predation risk. Food patch quality was statistically significant as the strongest cue to energetic return from a foraging bout. Correlation between distance and GUD was n ot statistically significant. Additional analyses indicated that the date of data collection (late spring through early fall) and GUD were positively correlated. A possible explanation of this finding is that the abundance of food resources becomes progressively sparse as fall approaches. As food resources are depleted over time, food sites at a greater distance may be more valuable. The decreasing availability of resources through the study period may necessitate more complete foraging at greater distances. Therefore, microhabitat and food patch quality in this study are statistically significant cues for energetic optimization, while the influence of distance may depend on the time of data collection.