|dc.description.abstract||Optimal foraging theory was developed as a theoretical framework for understanding the evolution of feeding strategies. It states that animals forage in a way that will maximize their net energy intake per unit time, thereby maximizing their individual fitness. A behavior whereby animals store surplus food that potentially can be consumed later is called caching. The eastern chipmunk (Tamias striatus) caches food in larder hoards and scatter hoards throughout the spring, summer, and fall. During each season I would observe eastern chipmunk activities.
To construct a preliminary time budget of chipmunk food acquisition and cache defensive behaviors, I observed eastern chipmunks throughout their period of above-ground activity for several hours each day. The study was conducted on a 4-ha plot in Hartman Creek State Park located north of Hartman Lake near Waupaca, Wisconsin. I live trapped T. striatus from late May to early June to uniquely mark individuals for focal observations. I conducted observations on all individuals (both marked and unmarked) from early June through October during 2013 and 2014. Four behaviors that I recorded were territorial/alarm calling, foraging, expelling conspecifics from a territory, and scanning for conspecifics or predators.
Including all individuals (marked and unmarked) from both years of the study, linear analysis of categorical data revealed a difference in the distributions of behaviors across months and between years. The month*year interaction was also significant. Using the marked male and female data from the 2014 field season, I looked at the difference in distribution between behaviors for sex and month. Linear analysis of categorical data of marked individuals from 2014 revealed that there were no differences between sexes, but distributions of behaviors across months varied. There was no month*sex interaction.
Additional research on behavior needs to be implemented because caching behaviors are poorly understood and have the potential to play a fundamental role in optimal foraging by eastern chipmunks. Studying food acquisition and cache defense are critical to developing a greater understanding of optimal foraging and central place foraging theory models.
In summary, I found that foraging is the predominant behavior than cache defense, but behaviors also change over a single season and from year to year, presumably in response to environmental changes. Because of this flexibility, predicting individual behaviors is difficult without knowing the environmental cues that are used by chipmunks. Therefore, optimal foraging theory and central place foraging theory currently have utility only at a broader conceptual level. Although theorists continue to develop models that attempt to predict the behaviors of individuals, my study has shown that developing accurate utilitarian models will be difficult without knowledge of environmental influences||en