Sorry to Eat and Run: A Lesson Plan for Testing Trade-off in Squirrel Behavior Using Giving Up Densities (GUDs)

All animals need to find and compete for food, shelter, and mates in order to survive and reproduce. They also need to avoid being eaten by predators. Optimal foraging theory provides a framework to examine the trade-offs individuals make while foraging for food, taking into account an animal's body condition, predation pressure, quality of food resources, and food patch availability in the habitat. Here we describe an activity that uses Giving Up Densities (GUDs), which could be used as part of a course-based undergraduate research experience (CURE) or as a stand-alone activity. GUDs provide an experimental approach to quantify the costs and benefits of foraging in a particular patch and is simple to measure in that it is literally the density of food remaining in a patch. However, its interpretation allows students to compare foraging decisions under different environmental conditions, between species, or with different food sources. This activity was designed to study the foraging behavior of squirrels, which are active during the day, forage on seeds, and are found on and around many college campuses, but it can be adapted to nocturnal animals, birds, or other vertebrates. This module is hands-on. Students weigh seeds, sift sand, walk out into the field with bags of sand and trays, and analyze data. The module can be designed at various levels of inquiry to suit the needs of a particular class. Further, students can work individually, in pairs, or in teams. Finally, students and instructors are encouraged to upload their data to a national dataset, which is available to instructors for use in the classroom to broaden the possible hypotheses and analyses students can explore. Primary Image: Students use feeding trays to examine cost-benefit ratios of foraging squirrels. Trail cameras can be used to verify what species are utilizing the food patches. In this image, two color morphs (black and gray) of one species, eastern gray squirrel (Sciurus carolinensis), forage in trays at the University of Wisconsin - Stevens Point. Additional Squirrel-Net Articles: * An Introduction to the Squirrel-Net Teaching Modules * Squirreling Around for Science: Observing Sciurid Rodents to Investigate Animal Behavior * How Many Squirrels Are in the Shrubs? A Lesson Plan for Comparing Methods for Population Estimation * Squirrels in Space: Using Radio Telemetry to Explore the Space Use and Movement of Sciurid Rodents * Squirreling from Afar: Adapting Squirrel-Net Modules for Remote Teaching and Learning